general_fact: 584 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 584 is the number of ways to color the vertices of a triangle with 12 colors, up to rotation.
trivia: 584 is an unremarkable number.
historical_date: August 6th is the day in 1926 that Harry Houdini performs his greatest feat, spending 91 minutes underwater in a sealed tank before escaping.