Fatto matematico: 5599 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Trivia: 5599 is a boring number.
Data storica: April 30th is the day in 1993 that Monica Seles is stabbed by Günter Parche, an obsessed fan, during a quarterfinal match of the 1993 Citizen Cup in Hamburg, Germany.