Fait mathématique: 61491 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Culture générale: 61491 is an uninteresting number.
Date historique: May 9th is the day in 1964 that Ngo Dinh Can, de facto ruler of central Vietnam under his brother President Ngo Dinh Diem before the family's toppling, is executed.