Fatto generale: 52503 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 52503 is an unremarkable number.
Trivia: 52503 is an unremarkable number.
Data storica: September 30th is the day in 1966 that the British protectorate of Bechuanaland declares its independence, and becomes the Republic of Botswana.