A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 8426160 can be evenly divided by 1 2 3 4 5 6 8 9 10 12 15 16 18 20 24 27 30 36 40 45 47 48 54 60 72 80 83 90 94 108 120 135 141 144 166 180 188 216 235 240 249 270 282 332 360 376 415 423 432 470 498 540 564 664 705 720 747 752 830 846 940 996 1,080 1,128 1,245 1,269 1,328 1,410 1,494 1,660 1,692 1,880 1,992 2,115 2,160 2,241 2,256 2,490 2,538 2,820 2,988 3,320 3,384 3,735 3,760 3,901 3,984 4,230 4,482 4,980 5,076 5,640 5,976 6,345 6,640 6,768 7,470 7,802 8,460 8,964 9,960 10,152 11,205 11,280 11,703 11,952 12,690 14,940 15,604 16,920 17,928 19,505 19,920 20,304 22,410 23,406 25,380 29,880 31,208 33,840 35,109 35,856 39,010 44,820 46,812 50,760 58,515 59,760 62,416 70,218 78,020 89,640 93,624 101,520 105,327 117,030 140,436 156,040 175,545 179,280 187,248 210,654 234,060 280,872 312,080 351,090 421,308 468,120 526,635 561,744 702,180 842,616 936,240 1,053,270 1,404,360 1,685,232 2,106,540 2,808,720 4,213,080 and 8,426,160, with no remainder.
Since 8,426,160 cannot be divided by just 1 and 8,426,160, it is not a prime number.