I didn't bother answering, so I cannot say who they claim to be.  I DID find out the phone number is supposedly in Raleigh, North Carolina.   That is a totally different district than where I live, so there is NO WAY an IRS
office in Raleigh, NC would have any reason to be contacting me.  
Most likely a scam of some sort.  
I have one of those Panasonic phones that blocks phone numbers  & it is a BLESSING!!

got this call and would not answer it.  Who do I report it to?

The whole number is 919831727127, it is a call from India from some loser pretending to be from the IRS.  DO NOT GIVE HIM INFORMATION ABOUT YOUR BANK ACCOUNT and report this to your local authorities.