Fait mathématique: 8591 is the number of partitions of 42 that do not contain 1 as a part.
Culture générale: 8591 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Date historique: July 9th is the day in 1922 that Johnny Weissmuller swims the 100 meters freestyle in 58.6 seconds breaking the world swimming record and the 'minute barrier'.