general_fact: 1624 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 1624 is the Stirling number of the first kind s(7,3).
trivia: 1624 is a boring number.
historical_date: June 11th is the day in 1972 that the Eltham Well Hall rail crash, caused by an intoxicated train driver, kills six people and injures 126.