general_fact: 6660 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 6660 is a boring number.
trivia: 6660 is an unremarkable number.
historical_date: March 26th is the day in 1999 that a jury in Michigan finds Dr. Jack Kevorkian guilty of second-degree murder for administering a lethal injection to a terminally ill man.