A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 5154396 can be evenly divided by 1 2 3 4 6 12 13 19 26 37 38 39 47 52 57 74 76 78 94 111 114 141 148 156 188 222 228 247 282 444 481 494 564 611 703 741 893 962 988 1,222 1,406 1,443 1,482 1,739 1,786 1,833 1,924 2,109 2,444 2,679 2,812 2,886 2,964 3,478 3,572 3,666 4,218 5,217 5,358 5,772 6,956 7,332 8,436 9,139 10,434 10,716 11,609 18,278 20,868 22,607 23,218 27,417 33,041 34,827 36,556 45,214 46,436 54,834 66,082 67,821 69,654 90,428 99,123 109,668 132,164 135,642 139,308 198,246 271,284 396,492 429,533 859,066 1,288,599 1,718,132 2,577,198 and 5,154,396, with no remainder.
Since 5,154,396 cannot be divided by just 1 and 5,154,396, it is not a prime number.