math_fact: 47531 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
trivia: 47531 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
historical_date: February 18th is the day in 1978 that the first Ironman Triathlon competition takes place on the island of Oahu, won by Gordon Haller.