Fait général: 56404 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fait mathématique: 56404 is an unremarkable number.
Culture générale: 56404 is an uninteresting number.
Date historique: June 5th is the day in 1975 that the United Kingdom holds its first country-wide referendum, on remaining in the European Economic Community (EEC).