Information can be found here:

Where can I find my citizen service number on my Dutch identity card? | Netherlands Worldwide

Here you can also find an example of where to find the Dutch BSN number on your identity card (ID card). On ID card’s issued after 2014 it’s on the back.

Here you can also find an example of where to find the Dutch BSN number on your identity card (ID card). On ID card’s issued before 2014 it’s on the front.