Fatto generale: 1711 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 1711 is a triangular number that is the product of two primes.
Trivia: 1711 is an uninteresting number.
Data storica: September 6th is the day in 1949 that Allied military authorities relinquish control of former Nazi Germany assets back to German control.