math_fact: 2937 is a value of n for which n and 5n together use each digit 1-9 exactly once.
trivia: 2937 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
historical_date: January 15th is the day in 1962 that the Derveni papyrus, Europe's oldest surviving manuscript dating to 340 BC, is found in northern Greece.