math_fact: 1578 is the number of Hamiltonian paths of a 3×8 rectangle graph.
trivia: 1578 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
historical_date: April 26th is the day in 1986 that a nuclear reactor accident occurs at the Chernobyl Nuclear Power Plant in the Soviet Union (now Ukraine), creating the world's worst nuclear disaster.