Mathematical fact: 91453 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Trivia: 91453 is an uninteresting number.
Historical date: May 22nd is the day in 1915 that Lassen Peak erupts with a powerful force, and is the only mountain other than Mount St. Helens to erupt in the continental US during the 20th century.