2389 = (2 * 1194) + 1 ;
hence not 2 divides 2389 by NAT_4:9; :: thesis:
2389 = (3 * 796) + 1 ;
hence not 3 divides 2389 by NAT_4:9; :: thesis:
2389 = (5 * 477) + 4 ;
hence not 5 divides 2389 by NAT_4:9; :: thesis:
2389 = (7 * 341) + 2 ;
hence not 7 divides 2389 by NAT_4:9; :: thesis:
2389 = (11 * 217) + 2 ;
hence not 11 divides 2389 by NAT_4:9; :: thesis:
2389 = (13 * 183) + 10 ;
hence not 13 divides 2389 by NAT_4:9; :: thesis:
2389 = (17 * 140) + 9 ;
hence not 17 divides 2389 by NAT_4:9; :: thesis:
2389 = (19 * 125) + 14 ;
hence not 19 divides 2389 by NAT_4:9; :: thesis:
2389 = (23 * 103) + 20 ;
hence not 23 divides 2389 by NAT_4:9; :: thesis:
2389 = (29 * 82) + 11 ;
hence not 29 divides 2389 by NAT_4:9; :: thesis:
2389 = (31 * 77) + 2 ;
hence not 31 divides 2389 by NAT_4:9; :: thesis:
2389 = (37 * 64) + 21 ;
hence not 37 divides 2389 by NAT_4:9; :: thesis:
2389 = (41 * 58) + 11 ;
hence not 41 divides 2389 by NAT_4:9; :: thesis:
2389 = (43 * 55) + 24 ;
hence not 43 divides 2389 by NAT_4:9; :: thesis:
2389 = (47 * 50) + 39 ;
hence not 47 divides 2389 by NAT_4:9; :: thesis:

end;

then for n being Element of NAT st 1 < n & n * n <= 2389 & n is prime holds
not n divides 2389 by XPRIMET1:30;
hence 2389 is prime by NAT_4:14; :: thesis: