general_fact: 7515 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 7515 is an uninteresting number.
trivia: 7515 is an uninteresting number.
historical_date: July 28th is the day in 1945 that a U.S. Army B-25 bomber crashes into the 79th floor of the Empire State Building killing 14 and injuring 26.