general_fact: 2100 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 2100 is divisible by its reverse.
trivia: 2100 is a boring number.
historical_date: September 30th is the day in 1791 that the first performance of The Magic Flute, the last opera by Mozart to make its debut, took place at Freihaus-Theater auf der Wieden in Vienna, Austria.