Fait mathématique: 1105 is the smallest number that can be written as the sum of 2 squares in 4 ways.
Culture générale: 1105 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Date historique: January 9th is the day in 1861 that Mississippi becomes the second state to secede from the Union before the outbreak of the American Civil War.