Fait général: 2638 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fait mathématique: 2638 is an unremarkable number.
Culture générale: 2638 is a boring number.
Date historique: March 22nd is the day in 1916 that the last Emperor of China, Yuan Shikai, abdicates the throne and the Republic of China is restored.