general_fact: 15511 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 15511 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
trivia: 15511 is a boring number.
historical_date: June 19th is the day in 1964 that the Civil Rights Act of 1964 is approved after surviving an 83-day filibuster in the United States Senate.