1722 (one thousand seven hundred [and] twenty-two) is the natural number following 1721 and preceding 1723.
In mathematics 1722 is an even composite number that is a pronic number, the product of exactly four distinct primes, a 4-digit term in the continued fraction for pi, and the least possible number of diagonals of simple convex polyhedron with 46 face.
It is the number of 8-node graphs that are not determined by their spectrum, and the number of strings of length 4 over a 7-letter alphabet that do not begin with a palindrome
1722 is most notable for being a Giuga number, specifically the third one, since it is a composite number whose prime factors , 2, 3, 7, and 41, divides . This can be expressed as: . It is the largest Giuga number with 4 prime factors.
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