Fait mathématique: 25215 is an unremarkable number.
Culture générale: 25215 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Date historique: January 12th is the day in 2007 that Comet C/2006 P1 (McNaught) reaches perihelion becoming the brightest comet in more than 40 years.