Fait général: 21351 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fait mathématique: 21351 is a boring number.
Culture générale: 21351 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Date historique: June 15th is the day in 1752 that Benjamin Franklin proves that lightning is electricity (traditional date, the exact date is unknown).