Fatto generale: 690 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 690 is the smallest number that can not be written as the sum of a triangular number, a cube, and a Fibonacci number.
Trivia: 690 is a boring number.
Data storica: November 20th is the day in 1739 that Start of the Battle of Porto Bello between British and Spanish forces during the War of Jenkins' Ear.