general_fact: 81606 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 81606 is an uninteresting number.
trivia: 81606 is a boring number.
historical_date: June 6th is the day in 1644 that the Qing Dynasty Manchu forces led by the Shunzhi Emperor capture Beijing during the collapse of the Ming Dynasty.