Fatto matematico: 6456 is a value of n for which the n^{th} prime begins with the digits of n.
Trivia: 6456 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Data storica: September 3rd is the day in 1798 that the week long battle of St. George's Caye begins between Spain and Britain off the coast of Belize.