Fatto matematico: 853 is the number of connected graphs with 7 vertices.
Trivia: 853 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Data storica: May 2nd is the day in 1885 that Cree and Assiniboine warriors win the Battle of Cut Knife, their largest victory over Canadian forces during the North-West Rebellion.