A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 8237880 can be evenly divided by 1 2 3 4 5 6 7 8 9 10 12 14 15 18 20 21 24 28 30 35 36 40 42 45 49 56 60 63 70 72 84 90 98 105 120 126 140 147 168 180 196 210 245 252 280 294 315 360 392 420 441 467 490 504 588 630 735 840 882 934 980 1,176 1,260 1,401 1,470 1,764 1,868 1,960 2,205 2,335 2,520 2,802 2,940 3,269 3,528 3,736 4,203 4,410 4,670 5,604 5,880 6,538 7,005 8,406 8,820 9,340 9,807 11,208 13,076 14,010 16,345 16,812 17,640 18,680 19,614 21,015 22,883 26,152 28,020 29,421 32,690 33,624 39,228 42,030 45,766 49,035 56,040 58,842 65,380 68,649 78,456 84,060 91,532 98,070 114,415 117,684 130,760 137,298 147,105 168,120 183,064 196,140 205,947 228,830 235,368 274,596 294,210 343,245 392,280 411,894 457,660 549,192 588,420 686,490 823,788 915,320 1,029,735 1,176,840 1,372,980 1,647,576 2,059,470 2,745,960 4,118,940 and 8,237,880, with no remainder.
Since 8,237,880 cannot be divided by just 1 and 8,237,880, it is not a prime number.