This number just showed up in an email spam I received for (illegal) sales of prescription drugs. I won't post the web site here but keep an eye out for any references to this number. Their web site also shows 866-210-9191 so I'll put another post under that number.
Oh, by the way: Both numbers appear on their web site in the form of graphics (images), not text. They do that so the numbers won't be picked up by search engines. I wonder why that might be...
Answering unknown numbers, either manually, or automatically, means you're playing their game. No kind of answer, you're not playing, and without a participant, no chance for the caller, whatever it may be they want.