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 boring number.
Data storica: January 4th is the day in 1976 that the Reavey and O'Dowd killings take place (part of The Troubles in Northern Ireland, United Kingdom).