A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 8330784 can be evenly divided by 1 2 3 4 6 7 8 11 12 14 16 21 22 23 24 28 32 33 42 44 46 48 49 56 66 69 77 84 88 92 96 98 112 132 138 147 154 161 168 176 184 196 224 231 253 264 276 294 308 322 336 343 352 368 392 462 483 506 528 539 552 588 616 644 672 686 736 759 784 924 966 1,012 1,029 1,056 1,078 1,104 1,127 1,176 1,232 1,288 1,372 1,518 1,568 1,617 1,771 1,848 1,932 2,024 2,058 2,156 2,208 2,254 2,352 2,464 2,576 2,744 3,036 3,234 3,381 3,542 3,696 3,773 3,864 4,048 4,116 4,312 4,508 4,704 5,152 5,313 5,488 6,072 6,468 6,762 7,084 7,392 7,546 7,728 7,889 8,096 8,232 8,624 9,016 10,626 10,976 11,319 12,144 12,397 12,936 13,524 14,168 15,092 15,456 15,778 16,464 17,248 18,032 21,252 22,638 23,667 24,288 24,794 25,872 27,048 28,336 30,184 31,556 32,928 36,064 37,191 42,504 45,276 47,334 49,588 51,744 54,096 56,672 60,368 63,112 74,382 85,008 86,779 90,552 94,668 99,176 108,192 120,736 126,224 148,764 170,016 173,558 181,104 189,336 198,352 252,448 260,337 297,528 347,116 362,208 378,672 396,704 520,674 595,056 694,232 757,344 1,041,348 1,190,112 1,388,464 2,082,696 2,776,928 4,165,392 and 8,330,784, with no remainder.
Since 8,330,784 cannot be divided by just 1 and 8,330,784, it is not a prime number.