Fait général: 6404 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fait mathématique: 6404 is a value of n for which n!!.
Culture générale: 6404 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Date historique: July 13th is the day in 1919 that the British airship R34 lands in Norfolk, England, completing the first airship return journey across the Atlantic in 182 hours of flight.