Fait mathématique: 15585 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Culture générale: 15585 is a boring number.
Date historique: September 1st is the day in 1836 that Narcissa Whitman, one of the first English-speaking white women to settle west of the Rocky Mountains, arrives at Walla Walla, Washington.