general_fact: 1554 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 1554 is the trinomial coefficient T(9,3).
trivia: 1554 is an uninteresting number.
historical_date: April 2nd is the day in 1972 that Actor Charlie Chaplin returns to the United States for the first time since being labeled a communist during the Red Scare in the early 1950s.