general_fact: 4741 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 4741 is a value of n for which 4n and 5n together use each digit exactly once.
trivia: 4741 is a boring number.
historical_date: December 23rd is the day in 1970 that the North Tower of the World Trade Center in Manhattan, New York City is topped out at 1,368 feet (417 m), making it the tallest building in the world.