Fatto matematico: 20668 is an uninteresting number.
Trivia: 20668 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Data storica: August 1st is the day in 1664 that the Ottoman Empire is defeated in the Battle of Saint Gotthard by an Austrian army led by Raimondo Montecuccoli, resulting in the Peace of Vasvár.