Fatto generale: 5511 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 5511 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Trivia: 5511 is an unremarkable number.
Data storica: February 1st is the day in 1989 that the Western Australian towns of Kalgoorlie and Boulder amalgamate to form the City of Kalgoorlie-Boulder.