I got a phone call from this number at 12:37 pm and didn't answer. Tried to call the number back and got a recording that said, "the number or code you have called is incorrect."

This number keeps calling me... no voicemail. 7201892472

Number has called a few times the past few weeks.  Same as above, no voicemail.  720-189-2472

Same.  I answered, and it said "Goodbye."  Think it's looking for active phone numbers.

This number has called repeatedly, but I don't answer an unknown number if it doesn't leave a message the first time. Guess I'll keep ignoring it, but sure would be nice to get it to stop.