Fatto generale: 21877 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 21877 is an unremarkable number.
Trivia: 21877 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Data storica: November 23rd is the day in 1499 that Pretender to the throne Perkin Warbeck is hanged for reportedly attempting to escape from the Tower of London.