Mathematical fact: 4260 is a value of n for which n+1, 2n+1, 3n+1, and 4n+1 are all prime.
Trivia: 4260 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Historical date: August 30th is the day in 1974 that a powerful bomb explodes at the Mitsubishi Heavy Industries headquarters in Marunouchi, Tokyo, Japan.