Fatto generale: 63313 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 63313 is an uninteresting number.
Trivia: 63313 is an unremarkable number.
Data storica: May 5th is the day in 1949 that the Treaty of London establishes the Council of Europe in Strasbourg as the first European institution working for European integration.