Complete list of area number groups from the Social Security Administration The middle two digits are the group number. They have no special geographic or data significance but merely serve to break the number into conveniently sized blocks for orderly issuance.he number is divided into three parts. The Area Number, the first three digits, is assigned by the geographical region. Prior to 1973, cards were issued in local Social Security offices around the country and the Area Number represented the office code in which the card was issued.