Fait général: 21913 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fait mathématique: 21913 is an uninteresting number.
Culture générale: 21913 is an unremarkable number.
Date historique: December 29th is the day in 1876 that the Ashtabula River Railroad bridge disaster occurs, leaving 64 injured and 92 dead at Ashtabula, Ohio.