Who called from 6105570070

If you call this number back, it is a recording saying 666.
What or who is this ?

"After heart attack"-Adult may qualify for a CVD clinical study (fourierstudy.com)1-866-207-3917.

666 how can we stop these annoyance calls received at least one per day?

This number called 6 times in a row, I answered 3 times, someone started talking and then disconnected, I called back and got the 666 message also.

Some type of heart study site?