General fact: 2456 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Mathematical fact: 2456 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Trivia: 2456 is a boring number.
Historical date: September 21st is the day in 2003 that Galileo mission is terminated by sending the probe into Jupiter's atmosphere, where it is crushed by the pressure at the lower altitudes.