general_fact: 2520 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 2520 is the least common multiple of every integer under 10.
trivia: 2520 is an uninteresting number.
historical_date: November 24th is the day in 1906 that the Canton Bulldogs-Massillon Tigers Betting Scandal, the first major scandal in professional American football.