general_fact: 21186 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 21186 is an uninteresting number.
trivia: 21186 is an uninteresting number.
historical_date: January 1st is the day in 1772 that the first traveler's cheques, which can be used in 90 European cities, go on sale in London, England, Great Britain.