It is really long number – NOT the drivers license number, not the SSN, not the your birthdate or anything like that. It is used internally as an identifier of YOU (person) even if other stuff changes.
In Texas it is on the front next to the letters DD. Not sure about California.

The audit number is on the license, it is separate from driver’s license number. I think you need the hard copy license to see the code. Sounds like you’ll have to go and get a replacement license.