A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1037232 can be evenly divided by 1 2 3 4 6 7 8 9 12 14 16 18 21 24 27 28 36 42 48 49 54 56 63 72 84 98 108 112 126 144 147 168 189 196 216 252 294 336 343 378 392 432 441 504 588 686 756 784 882 1,008 1,029 1,176 1,323 1,372 1,512 1,764 2,058 2,352 2,401 2,646 2,744 3,024 3,087 3,528 4,116 4,802 5,292 5,488 6,174 7,056 7,203 8,232 9,261 9,604 10,584 12,348 14,406 16,464 18,522 19,208 21,168 21,609 24,696 28,812 37,044 38,416 43,218 49,392 57,624 64,827 74,088 86,436 115,248 129,654 148,176 172,872 259,308 345,744 518,616 and 1,037,232, with no remainder.
Since 1,037,232 cannot be divided by just 1 and 1,037,232, it is not a prime number.