A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1839024 can be evenly divided by 1 2 3 4 6 8 9 11 12 16 18 22 24 27 33 36 43 44 48 54 66 72 81 86 88 99 108 129 132 144 162 172 176 198 216 243 258 264 297 324 344 387 396 432 473 486 516 528 594 648 688 774 792 891 946 972 1,032 1,161 1,188 1,296 1,419 1,548 1,584 1,782 1,892 1,944 2,064 2,322 2,376 2,673 2,838 3,096 3,483 3,564 3,784 3,888 4,257 4,644 4,752 5,346 5,676 6,192 6,966 7,128 7,568 8,514 9,288 10,449 10,692 11,352 12,771 13,932 14,256 17,028 18,576 20,898 21,384 22,704 25,542 27,864 34,056 38,313 41,796 42,768 51,084 55,728 68,112 76,626 83,592 102,168 114,939 153,252 167,184 204,336 229,878 306,504 459,756 613,008 919,512 and 1,839,024, with no remainder.
Since 1,839,024 cannot be divided by just 1 and 1,839,024, it is not a prime number.