Northern Mariana Islands?  Are you kidding me?  I had to google that.  It's halfway between Japan and Papua New Guinea.  Unless they're working at 2 in the morning or something like that I'm going to guess a spoofed number.  9-13-2016 came in while I was still in the process of entering the other two unwanted calls I got today.  3 calls in less than 2 hours.  lovely.  did not answer, no message left.  blocked.