Hecho matemático: 1257 is a value of n for which f(s(n)) = f(n).
Trivia: 1257 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fecha histórica: June 10th is the day in 1980 that the African National Congress in South Africa publishes a call to fight from their imprisoned leader Nelson Mandela.