Fatto generale: 21117 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 21117 is a boring number.
Trivia: 21117 is a boring number.
Data storica: October 24th is the day in 1911 that Orville Wright remains in the air 9 minutes and 45 seconds in a Wright Glider at Kill Devil Hills, North Carolina.