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 a number for which we're missing a fact (submit one to numbersapi at google mail!).
Data storica: January 4th is the day in 1998 that a massive ice storm hits eastern Canada and the northeastern United States, continuing through January 10 and causing widespread destruction.