General fact: 16564 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Mathematical fact: 16564 is an uninteresting number.
Trivia: 16564 is an unremarkable number.
Historical date: May 7th is the day in 1429 that Joan of Arc ends the Siege of Orléans, pulling an arrow from her own shoulder and returning, wounded, to lead the final charge.