Go to your settings then privacy and security thrn you can check your phone number visibility status whether you allow for everyone or your contacts or no body. I think this might help.

when they log in on your friends phone (who have your number ) then they get all the contacts including your number , may be this is the case

May be u didn't hide ur phone from profile....

You have to change your privacy settings

Ur username or user ID is probably betam common or basic. Like @beyonce or sth 🤷‍♀

Setting - privacy & Security - phone number Keza astekakyiw or astekaklew