for n being Element of NAT st 1 < n & n * n <= 881 & n is prime holds
not n divides 881

proof

let n be Element of NAT ; :: thesis: ( 1 < n & n * n <= 881 & n is prime implies not n divides 881 )
881 = (2 * 440) + 1 ;
then A1: not 2 divides 881 ;
881 = (3 * 293) + 2 ;
then A2: not 3 divides 881 by NAT_4:9;
881 = (5 * 176) + 1 ;
then A3: not 5 divides 881 by NAT_4:9;
881 = (7 * 125) + 6 ;
then A4: not 7 divides 881 by NAT_4:9;
881 = (11 * 80) + 1 ;
then A5: not 11 divides 881 by NAT_4:9;
881 = (13 * 67) + 10 ;
then A6: not 13 divides 881 by NAT_4:9;
881 = (17 * 51) + 14 ;
then A7: not 17 divides 881 by NAT_4:9;
881 = (19 * 46) + 7 ;
then A8: not 19 divides 881 by NAT_4:9;
881 = (23 * 38) + 7 ;
then A9: not 23 divides 881 by NAT_4:9;
881 = (29 * 30) + 11 ;
then not 29 divides 881 by NAT_4:9;
hence ( 1 < n & n * n <= 881 & n is prime implies not n divides 881 ) by A1, A2, A3, A4, A5, A6, A7, A8, A9, Th12; :: thesis: verum

end;

hence 881 is prime by NAT_4:14; :: thesis: verum