Who called from 3604510909

I've received multiple calls from 360-451-0909 who hang up when I say "hello" but do not hang up until I say something.  Any ideas?

I've gotten a few missed calls from this number and no message...

Apparently I've been entered into the dream of a lifetime sweepstakes and someone will be calling me about my new car shortly.  I told them I couldn't legally drive and hung up on them.

I've received multiple calls from 360-451-0909 who hang up say nada.

calls at least twice a day.  no one is there.  if i dont answer they do not leave a message, just call back.