This is what's called a "trunk" line - a phantom type of number that belongs to large businesses or organizations that shows up on caller IDs as a real number but when you call it back you get an automated message stating the number called is not a valid number. 404-793-5000 belongs to WellStar Kennestone Hospital in Marietta. I was in the hospital recently and when I called my boyfriend from my room, this is the number that consistently appeared on his caller ID. Hope this helps!