Hecho general: 56857 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Hecho matemático: 56857 is an uninteresting number.
Trivia: 56857 is an unremarkable number.
Fecha histórica: September 1st is the day in 1529 that the Spanish fort Sancti Spiritu, the first one built in modern Argentina, is destroyed by natives.