Fatto generale: 5539 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 5539 is an uninteresting number.
Trivia: 5539 is a boring number.
Data storica: March 1st is the day in 317 that Crispus and Constantine II, sons of Roman Emperor Constantine I, and Licinius Iunior, son of Emperor Licinius, are made Caesares.