A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3140424 can be evenly divided by 1 2 3 4 6 7 8 9 12 14 18 21 24 27 28 31 36 42 54 56 62 63 67 72 84 93 108 124 126 134 168 186 189 201 216 217 248 252 268 279 372 378 402 434 469 504 536 558 603 651 744 756 804 837 868 938 1,116 1,206 1,302 1,407 1,512 1,608 1,674 1,736 1,809 1,876 1,953 2,077 2,232 2,412 2,604 2,814 3,348 3,618 3,752 3,906 4,154 4,221 4,824 5,208 5,628 5,859 6,231 6,696 7,236 7,812 8,308 8,442 11,256 11,718 12,462 12,663 14,472 14,539 15,624 16,616 16,884 18,693 23,436 24,924 25,326 29,078 33,768 37,386 43,617 46,872 49,848 50,652 56,079 58,156 74,772 87,234 101,304 112,158 116,312 130,851 149,544 174,468 224,316 261,702 348,936 392,553 448,632 523,404 785,106 1,046,808 1,570,212 and 3,140,424, with no remainder.
Since 3,140,424 cannot be divided by just 1 and 3,140,424, it is not a prime number.