Fatto matematico: 2558 is the number of divisors of the 15^{th} perfect number.
Trivia: 2558 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Data storica: January 1st is the day in 414 that Galla Placidia, half-sister of Emperor Honorius, is married to the Visigothic king Ataulf at Narbonne.