Mathematical fact: 5737 is the smallest number that can not be formed using the digit 1 at most 22 times, together with the symbols +, × and ^.
Trivia: 5737 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Historical date: September 15th is the day in 1945 that a hurricane in southern Florida and the Bahamas destroys 366 planes and 25 blimps at NAS Richmond.