General fact: 4537 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Mathematical fact: 4537 is an unremarkable number.
Trivia: 4537 is an unremarkable number.
Historical date: June 2nd is the day in 1967 that Luis Monge is executed in Colorado's gas chamber, in the last pre-Furman execution in the United States.