57 (number)

57 (fifty-seven) is the natural number following 56 and preceding 58.

57 is semiprime[1] a Blum integer,[2] and a Leyland number.

[3] The split Lie algebra E⁠7+1/2⁠ has a 57-dimensional Heisenberg algebra as its nilradical, and the smallest possible homogeneous space for E8 is also 57-dimensional.

[5] The joke is that he is famous for working abstractly, without concrete examples.

However, while the veracity of this legend about Grothendieck is unclear, it is known that this very error was committed by another famous mathematician Hermann Weyl in a published article.