Fait général: 4478 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fait mathématique: 4478 is the number of fullerenes with 66 carbon atoms.
Culture générale: 4478 is an unremarkable number.
Date historique: April 4th is the day in 1721 that Sir Robert Walpole enters office as the first Prime Minister of the United Kingdom under King George I.