Fatto generale: 2573 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 2573 is the number of partitions of 35 that do not contain 1 as a part.
Trivia: 2573 is an unremarkable number.
Data storica: January 16th is the day in 27 BC that Gaius Julius Caesar Octavianus is granted the title Augustus by the Roman Senate, marking the beginning of the Roman Empire.