Fatto generale: 91583 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 91583 is an uninteresting number.
Trivia: 91583 is an unremarkable number.
Data storica: September 29th is the day in 1960 that Nikita Khrushchev, leader of Soviet Union, disrupts a meeting of the United Nations General Assembly with a number of angry outbursts.