1000 or one thousand is the natural number following 999 and preceding 1001. In most English-speaking countries, it can be written with or without a comma or sometimes a period separating the thousands digit: 1,000.
A group of one thousand units is sometimes known, from Ancient Greek, as a chiliad. A period of one thousand years may be known as a chiliad or, more often from Latin, as a millennium. The number 1000 is also sometimes described as a short thousand in medieval contexts where it is necessary to distinguish the Germanic concept of 1200 as a long thousand. It is the first 4-digit integer.
Notation
The decimal representation for one thousand is 1000—a one followed by three zeros, in the general notation; 1 × 103—in engineering notation, which for this number coincides with: 1 × 103 exactly—in scientific normalized exponential notation; 1 E+3 exactly—in scientific E notation. The SI prefix for a thousand units is "kilo-", abbreviated to "k"—for instance, a kilogram or "kg" is a thousand grams. This is sometimes extended to non-SI contexts, such as "ka" (kiloannum) being used as a shorthand for periods of 1000 years. In computer science, however, "kilo-" is used more loosely to mean 2 to the 10th power (1024 or 210). In the SI writing style, a non-breaking space can be used as a thousands separator, i.e., to separate the digits of a number at every power of 1000. Multiples of thousands are occasionally represented by replacing their last three zeros with the letter "K" or "k": for instance, writing "$30k" for $30,000 or using "Y2K" to denote the Year 2000 computer problem. A thousand units of currency, especially dollars or pounds, are colloquially called a grand. In the United States, this is sometimes abbreviated with a "G" suffix.
In mathematics A chiliagon is a 1000-sided polygon.
Numbers in the range 1001–1999
1001 to 1099
1001
1002
1004 1004 = 22 × 251. It is a heptanacci number.
1009 1009 is the smallest four-digit prime, a Lucky prime, and Chen prime. It is palindromic in bases 11, 15, 19, 24 and 28: (83811, 47415, 2F219, 1I124, 18128).
1011 1011 = 3 × 337. It is a Harshad number in bases 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75 (and 202 other bases). It is the largest natural number n such that 2n contains 101 and does not contain 11011. There are 1011 partitions of 1 into reciprocals of positive integers <= 16 Egyptian fraction.
1013 1013 is a prime number, a Sophie Germain prime, and a centered square number,
1016 1016 = 23 × 127. It is stella octangula number and a member of the Mian–Chowla sequence. There are 1016 surface points on a cube with edge-length 14.
1019 1019 is a Sophie Germain prime, a safe prime, and a Chen prime.
1021 1021 is a Lucky prime and a twin prime with 1019.
1023
1024
1025 1025 = 52 × 41. It is a Jacobsthal-Lucas number and the hypotenuse of a primitive Pythagorean triangle. It is a Proth number because 1025 = 210 + 1. It is a member of the Moser–de Bruijn sequence because its base-4 representation (1000014) contains only digits 0 and 1, or equivalently, it's a sum of distinct powers of 4 (45 + 40).
1028 1028 = 22 × 257. It is sum of totient function for first 58 integers.
1029 There are 1029 primes <= 213.
1031 1031 is a prime number, a Sophie Germain prime, a super-prime, and a Chen prime. It is the exponent and number of ones for the fifth base-10 repunit prime.
1033 1033 is a prime number and an emirp. It forms a twin prime pair with 1031.
1035 1035 = 32 × 5 × 23. It is a hexagonal number and the 45th triangular number.
1039 1039 is a Chen prime and a Lucky prime. There are 1039 partitions of 30 that do not contain 1 as a part.
1040 1040 = 24 × 5 × 13. There are 1040 pieces that could be seen in a 6 × 6 × 6 × 6 Rubik's Tesseract.
1046 1046 = 2 × 523. It is a coefficient of f(q), the 3rd order mock theta function.
1049 1049 is a prime number, a Sophie Germain prime, a highly cototient number, and a Chen prime.
1051 1051 is a prime number, a centered pentagonal number, and a centered decagonal number.
1056 1056 = 25 × 3 × 11. It is a pronic number.
1060 1060 = 22 × 5 × 53. It is the sum of the first twenty-five primes from 2 through 97 (the number of primes less than 100) and the sixth sum of 10 consecutive primes, starting with 23 through 131.
1061 1061 is a prime number, an emirp, and a twin prime with 1063. There are 1061 prime numbers between 1000 and 10000 (or, number of four-digit primes in decimal representation).
1063 1063 is a prime number, a super-prime, a twin prime with 1061, and the sum of seven consecutive primes (137 + 139 + 149 + 151 + 157 + 163 + 167)
1069 1069 is a prime number and an emirp.
1076 1076 = 22 × 269. There are 1076 strict trees weight 11.
1078 1078 = 2 × 72 × 11. It is an Euler transform of negative integers.
1080 1080 = 23 × 33 × 5. It is a pentagonal number and a largely composite number.
1081 1081 = 23 × 47. It is the 46th triangular number and a member of Padovan sequence.
1086 1086 = 2 × 3 × 181. It is a Smith number and the sum of totient function for the first 59 integers.
1087 1087 is a prime number, a super-prime, a cousin prime, and a lucky prime.
1089
1091 1091 is a prime number, a cousin prime, and a twin prime with 1093.
1093 1093 is a twin prime with 1091. Together with 1091 and 1097, it forms a prime triplet. It is a happy prime and a star prime. It is also the smallest Wieferich prime. 1093 is a repunit prime in base 3 because:
1097 1097 is a prime number, an emirp, and a Chen prime.
1100 to 1199
1102 1102 = 2 × 19 × 29. It is the sum of the totient function for the first 60 integers.
1103 1103 is a prime number, a Sophie Germain prime, and a balanced prime.
1104 1104 = 24 × 3 × 23. It is a Keith number
1105
1109 1109 is a Chen prime.
1113 1113 = 3 × 7 × 53. There are 1113 strict partitions of 40.
1117 1117 is a Chen prime. There are 1117 diagonally symmetric polyominoes with 16 cells.
1118 1118 = 2 × 13 × 43. There are 1118 unimodular 2 × 2 matrices having all terms in {0,1,...,21}.
1119 1119 = 3 × 373. There are 1119 bipartite graphs with 9 nodes.
1122 1122 = 2 × 3 × 11 × 17. It is a pronic number.
1123 1123 is a balanced prime.
1126 1126 = 2 × 563. There are 1126 2 × 2 non-singular integer matrices with entries from {0, 1, 2, 3, 4, 5}.
1127 1127 = 72 × 23. It is the maximum number of pieces that can be obtained by cutting an annulus with 46 cuts.
1128 1128 = 23 × 3 × 47. It is the 47th triangular number and the 24th hexagonal number. 1128 is the dimensional representation of the largest vertex operator algebra with central charge of 24, D24.
1151 is the first prime number following a prime gap of 22. It is also a Chen prime.
1152 1152 = 27 × 32. It is a highly totient number, a 3-smooth number, and an Achilles number.
1153 1153 is a super-prime and a Proth prime.
1159 1159 = 19 × 61. It is a centered octahedral number and a member of the Mian–Chowla sequence.
1160 1160 = 23 × 5 × 29. It is an octagonal number.
1161 1161 = 33 × 43. It is the sum of the first twenty-six primes.
1162 1162 = 2 × 7 × 83. It is the sum of the totient function for the first 61 integers and a pentagonal number.
1163
1163 is a Chen prime.
1164 1164 = 22 × 3 × 97. There are 1164 chains of multisets that partition a normal multiset of weight 8, where a multiset is normal if it spans an initial interval of positive integers
1169 1169 = 7 × 167. It is a highly cototient number
1171 1171 is a super-prime.
1173 1173 = 3 × 17 × 23. There are 1173 simple triangulations on a plane with 9 nodes.
1174 1174 = 2 × 587. There are 1174 widely totally strongly normal compositions of 16. .
1175 1175 = 52 × 47. It is the maximum number of pieces that can be obtained by cutting an annulus with 47 cuts.
1176 1176 = 23 × 3 × 72. It is the 48th triangular number.
1178 1178 = 2 × 19 × 31. There are 1178 surface points on a cube with edge-length 15.
1179 1179 = 32 × 131. There are 1179 different permanents of binary 7 by 7 matrices.
1182 1182 = 2 × 3 × 197. There are 1182 necklaces possible with 14 beads of 2 colors (that cannot be turned over). 1184 1184 = 25 × 37. It is an amicable number with 1210.
1186 1186 = 2 × 593. There are 1186 diagonally symmetric polyominoes with 15 cells.
1187 1187 is a safe prime, a Stern prime, a balanced prime, and a Chen prime. 1190 1190 = 2 × 5 × 7 × 17. It is a pronic number. Building a 28-tier house of cards requires 1190 cards.
1191 1191 = 3 × 397 = 352 - 35 + 1 = H35, the 35th Hogben number.
1192 1192 = 23 × 149. It is the sum of the totient function for the first 62 integers.
1193 1193 is a Chen prime.
41193 - 31193 is prime.
1198 1198 = 2 × 599. It is a centered heptagonal number.
1200 to 1299
1200 1200 = 24 × 3 × 52. There are 1200 households in the Nielsen ratings sample.Meehan, Eileen R., Why TV is not our fault: television programming, viewers, and who's really in control Lanham, MD: Rowman & Littlefield, 2005
1200 is known as the long thousand or ten "long hundreds" of 120 each. It is the traditional reckoning of large numbers in Germanic languages.
1201 1201 is a super-prime, a centered square number, and a centered decagonal number.
1202 1202 = 2 × 601. There are a maximum of 1202 regions when the plane is divided by 25 ellipses.
1203 1203 = 3 × 401. It is the smallest number greater than 1000 in the coordinating sequence for the (2,6,∞) tiling of the hyperbolic plane.
1204 1204 = 22 × 7 × 43. It is the magic constant for a 7 × 7 × 7 magic cube.
1205 1205 = 5 × 241. There are 1205 partitions of 28 such that the number of odd parts is a part
1207 1207 = 17 × 71. It is a composite de Polignac number.
1208 1208 = 23 × 151. There are 1208 strict chains of divisors starting with the superprimorial A006939(3).
1210 1210 = 2 × 5 × 112. It is an amicable number with 1184Higgins, ibid. and a Self-descriptive number.
1211 1211 = 7 × 173. It is a composite de Polignac number
1212 1212 = 22 × 3 × 101 = , where is the number of partitions of .
1213 1213 is a prime number and an emirp.
1214 1214 = 2 × 607. It is a spy number and the sum of the first 39 composite numbers.
1215 1215 = 35 × 5. There are 1215 edges in the hexagonal triangle T(27)
1216 1216 = 26 × 19. It is a nonagonal number
1217 1217 is a super-prime and a Proth prime.
1219 1219 = 23 × 53. It is a centered triangular number and a zero of Mertens function.
1220 1220 = 22 × 5 × 61. It is a zero of Mertens function. There are 1220 binary vectors of length 16 containing no singletons.
1222 1222 = 2 × 13 × 47. It is a hexagonal pyramidal number.
1223 1223 is the 200th prime number. It is also a Sophie Germain prime and a balanced prime.
1224 1224 = 23 × 32 × 17. There are 1224 edges in the join of two cycle graphs, both of order 34.
1225 1225 = 52 × 72 = 352. It is the smallest number greater than 1 to be a triangular number, a square number and a hexagonal number. It is the second square triangular number greater than 1. It is the 49th triangular number, the 35th square number, the 25th hexagonal number, a centered octagonal number, a 29-gonal number, a 60-gonal number, and a 124-gonal number. It is the sum of 5 consecutive odd cubes:
1225 = 13 + 33 + 53 + 73 + 93.
1226 1226 = 2 × 613. There are 1226 rooted identity trees with 15 nodes.
1228 1228 = 22 × 307. It is the sum of the totient function for the first 63 integers.
1229 1229 is a Sophie Germain prime and an emirp. There are 1229 primes less than 10,000.
1230 1230 = 2 × 3 × 5 × 41 = T(9, 6), the Mahonian number.
1231 1231 is a prime number and an emirp.
1232 1232 = 24 × 7 × 11. There are 1232 labeled ordered set of partitions of a 7-set into odd parts.
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