Fait général: 21191 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fait mathématique: 21191 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Culture générale: 21191 is an unremarkable number.
Date historique: January 6th is the day in 1907 that Maria Montessori opens her first school and daycare center for working class children in Rome, Italy.