Fait général: 21836 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fait mathématique: 21836 is an uninteresting number.
Culture générale: 21836 is an uninteresting number.
Date historique: October 13th is the day in 1881 that Revival of the Hebrew language as Eliezer Ben-Yehuda and friends agree to use Hebrew exclusively in their conversations.