general_fact: 54821 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 54821 is an unremarkable number.
trivia: 54821 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
historical_date: February 3rd is the day in 1918 that the Twin Peaks Tunnel in San Francisco, California begins service as the longest streetcar tunnel in the world at 11,920 feet (3,633 meters) long.