general_fact: 618 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 618 is the number of ternary square-free words of length 15.
trivia: 618 is an uninteresting number.
historical_date: September 9th is the day in 1513 that James IV of Scotland is defeated and dies in the Battle of Flodden Field, ending Scotland's involvement in the War of the League of Cambrai.