The number is 11 digits long, identifies exactly one person, and cannot be changed once assigned, except in specific situations (such as gender reassignment).
[1][2] The PESEL system was originally designed by the communist government of the Polish People's Republic to trace personal information about its citizens.
It is a direct offshoot from the previous system, Magister, which was designed to trace and record data about all individuals with a university degree.
A similar system of identification numbers exists for businesses, called REGON (from Rejestr Gospodarki Narodowej – Register of the National Economy).
Similarly, businesses and corporations are often required to state the number at which they appear in the register of businesses, KRS - National Judicial Register (Krajowy Rejestr Sądowy), or the Taxpayer Identification Number - NIP.