I always answer since it's my work # and I normally don't recognize numbers but this one has been calling me at all times for the last 2 weeks. They always hang up as soon as I say hello. I let it go to vm once to see if they would leave one but never did.
Called, no message. People in coments claim that tehy pick up and don't hear anything - that's because the machine on the other end is dialing a ton of numbers(some random, some from lists), and when you/someone picks up, it connects you to a telemarketer or a scammer.