general_fact: 7993 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 7993 is one less than twice its reverse.
trivia: 7993 is an uninteresting number.
historical_date: November 18th is the day in 1903 that the Hay-Bunau-Varilla Treaty is signed by the United States and Panama, giving the United States exclusive rights over the Panama Canal Zone.