“ The Social Security Board shall provide for the assignment of an account number to each person who is required by any Federal agency to have such a number but who has not previously been assigned such number by the Board. ”

“ The Board may accomplish this purpose by (a) assigning such numbers to individual persons, (b) assigning blocks of numbers to Federal agencies for reassignment to individual persons, or (c) making such other arrangements for the assignment of numbers as it may deem appropriate. ”