Fait général: 2557 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fait mathématique: 2557 is the number of proper divisors of the 15^{th} perfect number.
Culture générale: 2557 is a boring number.
Date historique: December 31st is the day in 1695 that a window tax is imposed in England, causing many householders to brick up windows to avoid the tax.