Fatto generale: 5533 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 5533 is the number of graphs with 10 vertices and 2 cycles.
Trivia: 5533 is an unremarkable number.
Data storica: February 23rd is the day in 1905 that Chicago attorney Paul Harris and three other businessmen meet for lunch to form the Rotary Club, the world's first service club.