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 1900 that the United States Senate accepts the Anglo-German treaty of 1899 in which the United Kingdom renounces its claims to the Samoan islands.