Fatto generale: 29857 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 29857 is an unremarkable number.
Trivia: 29857 is an uninteresting number.
Data storica: September 28th is the day in 1912 that the Ulster Covenant is signed by half a million Ultonians in opposition to the Third Irish Home Rule Bill.