general_fact: 497 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 497 is the number of graphs with 8 edges.
trivia: 497 is a boring number.
historical_date: May 11th is the day in 1967 that Andreas Papandreou, Greek economist and socialist politician, is imprisoned in Athens by the Greek military junta.