Same thing. I got 3 calls in one day from this number. I called back and got a pre-recorded message telling me that I could be removed from the calling list by pressing 1, so I did. Have no idea why they call and hang up though.
Same thing as the other guy, Got a few calls withing an hour or so of each other. I didn't answer and they did not leave a message. Other boards seem to indicate this is telemarketer call of some sort.