Each legal entity in the Netherlands receives a special identification number called btw-nummer shortly after the registration (btw is Dutch for “value-added tax”).
This number is necessary for invoicing, both domestic and international, and—obviously—for VAT payments.
So what’s so special about it? Well, it turns out that if you’re a self-employed entrepreneur, your VAT number is based upon your BSN identifier. Which is quite a blunder from the privacy point of view.