Fait général: 21687 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fait mathématique: 21687 is a boring number.
Culture générale: 21687 is a boring number.
Date historique: May 17th is the day in 1954 that the United States Supreme Court hands down a unanimous decision in Brown v. Board of Education of Topeka, Kansas.