Fait mathématique: 2471 is the smallest number that can not be formed using the numbers 2^{0}, 2^{1}, ... , 2^{6}, together with the symbols +, –, × and ÷.
Culture générale: 2471 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Date historique: October 6th is the day in 1973 that Egypt launches a coordinated attack with Syria against Israel leading to the Yom Kippur War.