Fatto generale: 2196 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 2196 is the only number n so that 2n, 3n, 7n, and 9n together contain every digit 1-9 exactly twice.
Trivia: 2196 is an uninteresting number.
Data storica: January 4th is the day in 1966 that a military coup takes place in Upper Volta (later Burkina Faso), dissolving the National Parliament and leading to a new national constitution.