general_fact: 4890 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 4890 is a narcissistic number in base 5.
trivia: 4890 is a boring number.
historical_date: May 21st is the day in 879 that Pope John VIII gives blessings to duke Branimir and to Croatian people, considered to be international recognition of the Croatian state.