No clue who it is. Probably some scam like most numbers. You can download and app called Mr. Number to hang up on calls or send to voicemail. It works great!
You can block the calls on your iPhone too, it just takes a little higher IQ than an Android user to figure it out. Tap the "i" next to the phone number, scroll to the bottom of the list and select "Block this Caller". No third-party software is required.
stop calling me! You are calling me at work & I have no idea who you are or why you are calling me. Are you trying to get me fired from my job?! No messages are ever left. Stop harrassing me.