57 (number)
57 is the natural number following 56 and preceding 58. It is a composite number.
In mathematics
57 is a semiprime, a Blum integer, and a Leyland number.The split Lie algebra E has a 57-dimensional Heisenberg algebra as its nilradical, and the smallest possible homogeneous space for E8 is also 57-dimensional.
Although fifty-seven is not prime, it is jokingly known as the Grothendieck prime after a legend in which the mathematician Alexander Grothendieck gave it as an example of a prime number, not realizing it was divisible by three and nineteen. The same error was made by another famous mathematician, Hermann Weyl, in a published article.