Fatto generale: 676 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 676 is the smallest palindromic square number whose square root is not palindromic.
Trivia: 676 is a boring number.
Data storica: November 6th is the day in 1965 that Cuba and the United States formally agree to begin an airlift for Cubans who want to go to the United States.