So you don't have to look it up because it isn't displayed here, 773 (http://areacode.org/773) is the areacode for the part of Chicago surrounding, but not including, the central portion of Chicago. The downtown and near downtown area is the original 312 (http://areacode.org/312) areacode.
stays => starts
(Thanks "spell-check") :-(
"NAME NOT FOUND"? No kidding! This isn't even a valid number as far as I know. What exchange stays with a "1"? None that I know of anywhere here in the U.S.
This appears to be a blatant attempt to hide the originating number, yet not bother anyone when people try to call it back. I suppose people should thank them for that, but it would be nice if numbers couldn't be spoofed like this, (except in legitimate cases, of course.)