General fact: 904 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Mathematical fact: 904 is an unremarkable number.
Trivia: 904 is an unremarkable number.
Historical date: June 22nd is the day in 1978 that Charon, a satellite of the dwarf planet Pluto, is discovered by American astronomer James W. Christy.