A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 902496 can be evenly divided by 1 2 3 4 6 7 8 12 14 16 17 21 24 28 32 34 42 48 51 56 68 79 84 96 102 112 119 136 158 168 204 224 237 238 272 316 336 357 408 474 476 544 553 632 672 714 816 948 952 1,106 1,264 1,343 1,428 1,632 1,659 1,896 1,904 2,212 2,528 2,686 2,856 3,318 3,792 3,808 4,029 4,424 5,372 5,712 6,636 7,584 8,058 8,848 9,401 10,744 11,424 13,272 16,116 17,696 18,802 21,488 26,544 28,203 32,232 37,604 42,976 53,088 56,406 64,464 75,208 112,812 128,928 150,416 225,624 300,832 451,248 and 902,496, with no remainder.
Since 902,496 cannot be divided by just 1 and 902,496, it is not a prime number.