general_fact: 4191 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 4191 is the number of graphs with 12 vertices and 10 edges.
trivia: 4191 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
historical_date: June 22nd is the day in 1911 that George V and Mary of Teck are crowned King and Queen of the United Kingdom of Great Britain and Ireland.