general_fact: 16839 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 16839 is an uninteresting number.
trivia: 16839 is an uninteresting number.
historical_date: February 6th is the day in 1820 that the first 86 African American immigrants sponsored by the American Colonization Society started a settlement in present-day Liberia.