General fact: 2304 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Mathematical fact: 2304 is the number of edges in a 9 dimensional hypercube.
Trivia: 2304 is a boring number.
Historical date: April 22nd is the day in 1529 that Treaty of Saragossa divides the eastern hemisphere between Spain and Portugal along a line 297.5 leagues or 17° east of the Moluccas.