general_fact: 18898 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 18898 is a boring number.
trivia: 18898 is an uninteresting number.
historical_date: September 27th is the day in 1949 that the first Plenary Session of the National People's Congress approves the design of the Flag of the People's Republic of China.