A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 411264 can be evenly divided by 1 2 3 4 6 7 8 9 12 14 16 17 18 21 24 27 28 32 34 36 42 48 51 54 56 63 64 68 72 84 96 102 108 112 119 126 128 136 144 153 168 189 192 204 216 224 238 252 272 288 306 336 357 378 384 408 432 448 459 476 504 544 576 612 672 714 756 816 864 896 918 952 1,008 1,071 1,088 1,152 1,224 1,344 1,428 1,512 1,632 1,728 1,836 1,904 2,016 2,142 2,176 2,448 2,688 2,856 3,024 3,213 3,264 3,456 3,672 3,808 4,032 4,284 4,896 5,712 6,048 6,426 6,528 7,344 7,616 8,064 8,568 9,792 11,424 12,096 12,852 14,688 15,232 17,136 19,584 22,848 24,192 25,704 29,376 34,272 45,696 51,408 58,752 68,544 102,816 137,088 205,632 and 411,264, with no remainder.
Since 411,264 cannot be divided by just 1 and 411,264, it is not a prime number.