What is also important is to check what access rights an app requires before installing. When I see that a calculator app needs access to the phone book, I wonder.
A colleague has my phone number, saves it and some dubious app reads the number and no one other than the app programmer knows what happens to it.
Maybe I’m a little paranoid about this, but I do know why I rarely give my phone number to anyone. If you want to reach me from my circle of friends, you have to do so via Telegram or Facebook Messenger.