My car was hit by someone with Geico insurance - I have to say that Geico did a really nice job taking care of me (I was hit by 2 cars and the other insurance company gave me almost nothing even though their client totaled my car) - but anyhow, I assume this is Geico calling to see if everything was OK.
It's definitely GEICO, which I do have an auto policy with. When I called them, they have no record of anyone trying to call me from their claims or service department. I guess if it's important they will call back and leave a message.
GEICO uses this number as a callback number for the dispatch center for their roadside assistance department. they sometimes reach members to confirm location.