Fait général: 20571 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fait mathématique: 20571 is an unremarkable number.
Culture générale: 20571 is an uninteresting number.
Date historique: April 26th is the day in 1981 that Dr. Michael R. Harrison of the University of California, San Francisco Medical Center performs the world's first human open fetal surgery.