On 8.6.2014 I received a call from this number, too. No caller ID. I did not answer and no message was left. Interestingly, I had recently been on the phone with Blue Cross/Blue Shield, as "scamfighter" stated the caller represented themselves, when spoken with.
Same issue. Called BCBS/IL yesterday and now have received 3 calls from this number today with no messages. Perhaps an issue with a follow up customer service survey?
Got two calls last evening after having spoken with BlueCross/Shield customer service earlier in the day. The two calls were at 7:00 pm and 9:40 pm (!). Did not answer either one. No caller id, no message.