That’d be the BSN.
The Dutch Citizen Service Number (BSN) is your official national
identification in the Netherlands. It replaced the old social security
number (sofinummer) in 2007. The Dutch BSN was introduced in July 2007
to enhance the efficiency of government administration and improve
public service delivery to citizens.The BSN in the Netherlands is closely linked with the national
register (BRP). Registering with the BRP is key to getting your
Citizen Service Number in the Netherlands. Once you have registered
with the BRP, you will be issued with a Dutch BSN which will be needed
for any interactions with the Dutch government or public services,
from receiving social security or healthcare to enrolling for study or
paying tax. This means that the BSN functions as a social security
number, a national identification number and a tax number in the
Netherlands.Whereas the sofinummer was the responsibility of the Dutch tax
authority (Belastingdienst), the Dutch BSN is administered by the
Ministry of the Interior (BZK) and issued by the local municipalities.
It is a unique 8 or 9 digit number which can be found on Dutch
passports, national ID cards and driving licences.
Credit:stackoverflow.com‘