Fatto generale: 21877 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 21877 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Trivia: 21877 is an uninteresting number.
Data storica: November 23rd is the day in 1934 that an Anglo-Ethiopian boundary commission in the Ogaden discovers an Italian garrison at Walwal, well within Ethiopian territory.