general_fact: 20517 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 20517 is an uninteresting number.
trivia: 20517 is a boring number.
historical_date: March 3rd is the day in 1904 that Kaiser Wilhelm II of Germany becomes the first person to make a sound recording of a political document, using Thomas Edison's phonograph cylinder.