Fait général: 91921 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fait mathématique: 91921 is an unremarkable number.
Culture générale: 91921 is an unremarkable number.
Date historique: September 2nd is the day in 1752 that Great Britain adopts the Gregorian calendar, nearly two centuries later than most of Western Europe.