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 1818 that the United States Congress adopts the flag of the United States with 13 red and white stripes and one star for each state (then 20).