general_fact: 564 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 564 is the number of 13-ominoes with a horizontal or vertical line of symmetry.
trivia: 564 is a boring number.
historical_date: July 17th is the day in 1976 that the opening of the Summer Olympics in Montreal is marred by 25 African teams boycotting the New Zealand team.