Mathematical fact: 338 is the smallest number for which both the number of divisors and the sum of its prime factors is a perfect number.
Trivia: 338 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Historical date: December 3rd is the day in 1992 that a test engineer for Sema Group uses a personal computer to send the world's first text message via the Vodafone network to the phone of a colleague.