Fatto generale: 5611 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 5611 is the smallest number for which it and the 3 numbers before and after it all have f(n) divisible by 10.
Trivia: 5611 is a boring number.
Data storica: May 12th is the day in 1937 that George VI and Elizabeth Bowes-Lyon are crowned King and Queen of the United Kingdom of Great Britain and Northern Ireland.