A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 8066304 can be evenly divided by 1 2 3 4 6 8 9 12 16 18 24 27 32 36 48 54 64 72 81 96 108 128 144 162 192 216 256 288 324 384 389 432 576 648 768 778 864 1,152 1,167 1,296 1,556 1,728 2,304 2,334 2,592 3,112 3,456 3,501 4,668 5,184 6,224 6,912 7,002 9,336 10,368 10,503 12,448 14,004 18,672 20,736 21,006 24,896 28,008 31,509 37,344 42,012 49,792 56,016 63,018 74,688 84,024 99,584 112,032 126,036 149,376 168,048 224,064 252,072 298,752 336,096 448,128 504,144 672,192 896,256 1,008,288 1,344,384 2,016,576 2,688,768 4,033,152 and 8,066,304, with no remainder.
Since 8,066,304 cannot be divided by just 1 and 8,066,304, it is not a prime number.