math_fact: 15871 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
trivia: 15871 is an unremarkable number.
historical_date: June 14th is the day in 1965 that Nguyen Cao Ky became Prime Minister of South Vietnam at the head of a military junta; General Nguyen Van Thieu became the figurehead chief of state.