Fait mathématique: 9857 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Culture générale: 9857 is an unremarkable number.
Date historique: December 26th is the day in 2003 that a magnitude 6.6 earthquake devastates southeast Iranian city of Bam, killing tens of thousands and destroying the citadel of Arg-é Bam.