general_fact: 7421 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 7421 is a value of n for which 4n and 5n together use each digit exactly once.
trivia: 7421 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
historical_date: April 25th is the day in 1707 that the Habsburg army is defeated by Bourbon army at Almansa (Spain) in the War of the Spanish Succession.