Fait mathématique: 21945 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Culture générale: 21945 is an unremarkable number.
Date historique: January 30th is the day in 1911 that the destroyer USS Terry (DD-25) makes the first airplane rescue at sea saving the life of James McCurdy 10 miles from Havana, Cuba.