Removing a number from lg g pad f 8.0

I have paid off the device, and it is no longer associated with a data plan from AT&T almost two years ago. The device stopped working, being unable to turn on, due to a software update, presumably, and for months it was just in a box stored away. I found it a few days ago, and somehow it fired up, so I decided I'd use it for just Wi-Fi and have another portable device to carry around. In the settings, the number is still listed as the one associated with it when it was working prior. When contacting AT&T I was told that the number had been given to someone else (which is completely understandable.) I would like to have this number not listed as my device's, as it's no longer mine. Is there a way to remove it?