u/iptv_inquirer

I'm stumped. I recently did a factory reset of my iPhone SE 3d gen. This phone was bought new (way back when)
After the reset and after the normal setup, I signed in to my Apple account and setup my Facetime and noticed my email address and my phone number for my caller ID. There's my phone number where I can be reached but there's another phone number below mine. I've never seen that number and have no idea where that number came from. That's really weird!
Any help would be greatly appreciated.