General fact: 41539 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Mathematical fact: 41539 is a boring number.
Trivia: 41539 is an unremarkable number.
Historical date: September 23rd is the day in 1845 that the Knickerbockers Baseball Club, the first baseball team to play under the modern rules, is founded in New York.