Mathematical fact: 2783 is the smallest number whose 9^{th} power has 31 digits.
Trivia: 2783 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Historical date: August 14th is the day in 1816 that the United Kingdom formally annexed the Tristan da Cunha archipelago, ruling them from the Cape Colony in South Africa.