Yeah, and as I said, there are people hacking places for information an selling lists of stuff online. For example, the information in a Line account, will include your phone number as it´s connected to that. More you have other chat applications which do the same, that also can be hacked.
As another question. Have you ever used your phone number online when register for something, buying something or verifying an account? I think you have at some occasions as most of us do. That means more are aware of your phone number.
That, I took for granted, that you had checked already.