math_fact: 4253 is the exponent of a Mersenne prime.
trivia: 4253 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
historical_date: August 23rd is the day in 1944 that Freckleton Air Disaster – A United States Army Air Forces B-24 Liberator bomber crashes into a school in Freckleton, England killing 61 people.