let print_number number =
 let rec print_max_n n out =
   if (String.length out) > n
   then let linelen = n - 1
    in printf "%s\\\n%!" (String.sub out 0 linelen);
    print_max_n n (String.sub out linelen (String.length out - linelen))
   else printf "%s\n%!" out
 in print_max_n 70 (string_of_bigint number)