Fatto generale: 91839 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 91839 is a boring number.
Trivia: 91839 is an uninteresting number.
Data storica: June 12th is the day in 1979 that Bryan Allen wins the second Kremer prize for a man powered flight across the English Channel in the Gossamer Albatross.