A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 4088448 can be evenly divided by 1 2 3 4 6 7 8 9 12 13 14 16 18 21 24 26 27 28 32 36 39 42 48 52 54 56 63 64 72 78 84 91 96 104 108 112 117 126 128 144 156 168 169 182 189 192 208 216 224 234 252 273 288 312 336 338 351 364 378 384 416 432 448 468 504 507 546 576 624 672 676 702 728 756 819 832 864 896 936 1,008 1,014 1,092 1,152 1,183 1,248 1,344 1,352 1,404 1,456 1,512 1,521 1,638 1,664 1,728 1,872 2,016 2,028 2,184 2,366 2,457 2,496 2,688 2,704 2,808 2,912 3,024 3,042 3,276 3,456 3,549 3,744 4,032 4,056 4,368 4,563 4,732 4,914 4,992 5,408 5,616 5,824 6,048 6,084 6,552 7,098 7,488 8,064 8,112 8,736 9,126 9,464 9,828 10,647 10,816 11,232 11,648 12,096 12,168 13,104 14,196 14,976 16,224 17,472 18,252 18,928 19,656 21,294 21,632 22,464 24,192 24,336 26,208 28,392 31,941 32,448 34,944 36,504 37,856 39,312 42,588 44,928 48,672 52,416 56,784 63,882 64,896 73,008 75,712 78,624 85,176 97,344 104,832 113,568 127,764 146,016 151,424 157,248 170,352 194,688 227,136 255,528 292,032 314,496 340,704 454,272 511,056 584,064 681,408 1,022,112 1,362,816 2,044,224 and 4,088,448, with no remainder.
Since 4,088,448 cannot be divided by just 1 and 4,088,448, it is not a prime number.