Fait mathématique: 66366 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Culture générale: 66366 is a boring number.
Date historique: September 13th is the day in 585 BC that Lucius Tarquinius Priscus, king of Rome, celebrates a triumph for his victories over the Sabines, and the surrender of Collatia.