Fatto generale: 1706 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 1706 is 5 × 6 × 7 × 8 + 5 + 6 + 7 + 8.
Trivia: 1706 is an unremarkable number.
Data storica: September 1st is the day in 1970 that Attempted assassination of King Hussein of Jordan by Palestinian guerrillas, who attacked his motorcade.