General fact: 8904 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Mathematical fact: 8904 is an unremarkable number.
Trivia: 8904 is a boring number.
Historical date: May 17th is the day in 1814 that the Constitution of Norway is signed and the Danish Crown Prince Christian Frederik is elected King of Norway by the Norwegian Constituent Assembly.