Fatto matematico: 52421 is an unremarkable number.
Trivia: 52421 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Data storica: July 10th is the day in 1460 that Richard Neville, 16th Earl of Warwick defeats the king's Lancastrian forces and takes King Henry VI prisoner in the Battle of Northampton.