I recieved a call from this number last week and today. The call was from the security clearance expo folks. I asked how they had my number and they said they found it on my posted resume online. Since my resume is online with clearance info, it seems feasible.
I have gotten many calls in the last week from this unknown number. No messages are ever left. I am assuming this is a telemarketer, which I have already been put on the "do not call" list. Hmmm