general_fact: 457 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 457 is the index of a prime Euclid number.
trivia: 457 is an uninteresting number.
historical_date: April 1st is the day in 1989 that Margaret Thatcher's new local government tax, the Community Charge (commonly known as the "poll tax"), is introduced in Scotland.