A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 2508792 can be evenly divided by 1 2 3 4 6 8 11 12 13 17 22 24 26 33 34 39 43 44 51 52 66 68 78 86 88 102 104 129 132 136 143 156 172 187 204 221 258 264 286 312 344 374 408 429 442 473 516 559 561 572 663 731 748 858 884 946 1,032 1,118 1,122 1,144 1,326 1,419 1,462 1,496 1,677 1,716 1,768 1,892 2,193 2,236 2,244 2,431 2,652 2,838 2,924 3,354 3,432 3,784 4,386 4,472 4,488 4,862 5,304 5,676 5,848 6,149 6,708 7,293 8,041 8,772 9,503 9,724 11,352 12,298 13,416 14,586 16,082 17,544 18,447 19,006 19,448 24,123 24,596 28,509 29,172 32,164 36,894 38,012 48,246 49,192 57,018 58,344 64,328 73,788 76,024 96,492 104,533 114,036 147,576 192,984 209,066 228,072 313,599 418,132 627,198 836,264 1,254,396 and 2,508,792, with no remainder.
Since 2,508,792 cannot be divided by just 1 and 2,508,792, it is not a prime number.