Hecho general: 5050 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Hecho matemático: 5050 is the sum of the first 100 integers.
Trivia: 5050 is an uninteresting number.
Fecha histórica: October 28th is the day in 1834 that the Battle of Pinjarra is fought in the Swan River Colony in present-day Pinjarra, Western Australia.