Fatto matematico: 1571 is the smallest number that can not be formed using the digit 1 at most 23 times, together with the symbols +, –, × and ÷.
Trivia: 1571 is an unremarkable number.
Data storica: April 19th is the day in 1809 that an Austrian corps is defeated by the forces of the Duchy of Warsaw in the Battle of Raszyn, part of the struggles of the Fifth Coalition.