On a job application site for my local government it reveals if a specific social security has been used or not on that site. The site is very outdated.
Here is a reminder for all US citizens.
Your social security number is simply a serial number with zero checksums or any logic built in.
If you want another valid social security number you can simply pick a number before or after your own.
The social security number was never designed to be a general ID number, and should not be used as such.