general_fact: 4749 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 4749 is an uninteresting number.
trivia: 4749 is an uninteresting number.
historical_date: December 31st is the day in 1998 that the European Exchange Rate Mechanism freezes the values of the legacy currencies in the Eurozone, and establishes the value of the euro currency.