I keep getting a call from this number. Generally it is business hours. No message is ever left. When I have picked it up there is no sound on the other end.

I keep getting this number too.  It kind of freaks me out, because a lot of the time I am on the internet and it makes me think that they are trying to hack into my computer or something.  But you are right!  They never say anything when you do answer, and they never leave a message.

Weird.  I should probably call my phone company and have them block the number.