Fatto matematico: 617 is 1!^{2} + 2!^{2} + 3!^{2} + 4!^{2}.
Trivia: 617 is an unremarkable number.
Data storica: September 8th is the day in 1380 that Battle of Kulikovo – Russian forces defeat a mixed army of Tatars and Mongols, stopping their advance.