general_fact: 21704 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 21704 is a boring number.
trivia: 21704 is a boring number.
historical_date: June 3rd is the day in 1968 that Valerie Solanas, author of SCUM Manifesto, attempts to assassinate Andy Warhol by shooting him three times.