Engine number prefix different on engine vs. documents?

I recently bought a used Toyota Prius 2010 from a dealer. The engine number of the car as per the Service & Warranty book, vehicle history confirmation certificate, dealer's invoice etc. starts with 1ZX followed by a 7 digit number.
However, the number on the engine starts with 2ZR followed by the 7 digit number. The 7 digit numbers are the same on the engine and all the documents, but the prefixes aren't (2ZR vs. 1ZX).

Can someone confirm if this is expected? The 2ZR prefix is embossed on the engine in bigger text compared to the 7 digit number - so I am not exactly sure if that should be read along with the 7 digit number which is embossed in (relatively) smaller text.

What does it mean if the prefixes are different but the 7 digits that follow it are the same?

 

Thanks @rjparker. There are two numbers provided in the dealer's invoice and other documents.
1. VIN / Chassis /Frame No : This is the 17 digit string code that you have described. This matches exactly with what is on the vehicle. So no problems here.
2. Engine number : 1ZX******* (in all documents) but 2ZR******* embossed on the engine. The last seven digits of the engine numbers in the documents and on the engine are the same, but the first three characters are different (1ZX vs. 2ZR).

@PriusCamper - Thanks. Basis your suggestion, I have registered on the Toyota UK owner's website. I was able to get details of the vehicle's service history.