It's apparently American Express. I've been ignoring the number but finally answered it. The person was very rude, as per usual. Couldn't understand the name, Hussein something. Got nasty with me, so I got nasty with him. Told him he's in violation of the DNC list and American Express will be subjected to $9K in fines.
It's a scam caller claiming to be AmEx, "vishing" for account information. You can read about my experience here, if you'd like: http://tinyurl.com/6cxlgcu
If you have an AmEx account, I recommend calling their official customer service number (probably listed on the back of your card or on their official website) before calling this number.