I keep getting calls from this number. It only rings once. It is being blocked somehow-like to know who is calling.

They called at 1:57pm - BLOCKED at 1:58pm
We never answer unknown calls - EVER!  They are always scams.
You have had an answer machine for years - NOW is the time to purchase a blocking telephone or a blocking device that can block entire area codes.  We have both and the work!
Save your sanity - check Amazon for blocking phones (Panasonic - blocks 250 numbers) or a blocking device that can block entire area codes (D***tone Call Blocker).

Well stated!  We purchased a call-blocking machine capable of blocking entire area codes plus we have the capability of blocking 1200 numbers (200 are already pre-programmed, but that still leaves us 1,000 spaces to fill - and believe me - we WILL fill them).  Plus, call-blocking machines are NOT that expensive and you will definitely enjoy the peace and quiet a call blocking machine will give you!