Fait général: 20409 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fait mathématique: 20409 is a boring number.
Culture générale: 20409 is an uninteresting number.
Date historique: November 16th is the day in 2000 that Bill Clinton becomes the first U.S. President to visit Vietnam since the end of the Vietnam War.