General fact: 21947 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Mathematical fact: 21947 is a boring number.
Trivia: 21947 is an unremarkable number.
Historical date: February 1st is the day in 1968 that Canada's three military services, the Royal Canadian Navy, the Canadian Army and the Royal Canadian Air Force, are unified into the Canadian Forces.