Do you have an unlimited text plan? :0 (I don't!)
I "hear you" about curiosity, but this could be the beginning of something less than pleasurable in your life.
Numbers from Google, Skype and others do not necessarily follow conventional phone number issuance guidelines. You could easily get a phone number with an area code that is no where close to your actual location.
If the spamming continues, I suggest that you change your number.