56 (fifty-six) is the natural number following 55 and preceding 57.
Mathematics
56 is a composite number with prime factorization . Its proper divisors are 1, 2, 4, 7, 8, 14, and 28, whose sum is 64, so 56 is an abundant number. It is also a semiperfect number, since .
56 is a tetrahedral number, since . It is also a pronic number, since , and a tetranacci number.
56 is an Erdős–Woods number, meaning that there is an interval of 57 consecutive integers in which every element has a nontrivial common factor with one of the two endpoints.
In Lie theory, the exceptional Lie algebra has a fundamental representation of dimension 56.
Mythology PlutarchPlutarch, Moralia V: 30 states that the Pythagoreans associated a polygon of 56 sides with Typhon and that they associated certain polygons of smaller numbers of sides with other figures in Greek mythology.
Organizations The symbol of the Hungarian Revolution of 1956. Brazilian politician Enéas Carneiro had an odd way of repeating the number of his party, "Fifty-Six" (, in Portuguese), making it a widely repeated jargon in Brazil.
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