general_fact: 6473 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 6473 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
trivia: 6473 is an unremarkable number.
historical_date: September 20th is the day in 2000 that the British MI6 Secret Intelligence Service building is attacked by unapprehended forces using a Russian-built RPG-22 anti-tank missile.