Fait général: 21866 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fait mathématique: 21866 is an uninteresting number.
Culture générale: 21866 is an unremarkable number.
Date historique: November 12th is the day in 1980 that the NASA space probe Voyager I makes its closest approach to Saturn and takes the first images of its rings.