A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 8675640 can be evenly divided by 1 2 3 4 5 6 8 9 10 12 15 18 20 24 27 29 30 36 40 45 54 58 60 72 87 90 108 116 120 135 145 174 180 216 232 261 270 277 290 348 360 435 522 540 554 580 696 783 831 870 1,044 1,080 1,108 1,160 1,305 1,385 1,566 1,662 1,740 2,088 2,216 2,493 2,610 2,770 3,132 3,324 3,480 3,915 4,155 4,986 5,220 5,540 6,264 6,648 7,479 7,830 8,033 8,310 9,972 10,440 11,080 12,465 14,958 15,660 16,066 16,620 19,944 24,099 24,930 29,916 31,320 32,132 33,240 37,395 40,165 48,198 49,860 59,832 64,264 72,297 74,790 80,330 96,396 99,720 120,495 144,594 149,580 160,660 192,792 216,891 240,990 289,188 299,160 321,320 361,485 433,782 481,980 578,376 722,970 867,564 963,960 1,084,455 1,445,940 1,735,128 2,168,910 2,891,880 4,337,820 and 8,675,640, with no remainder.
Since 8,675,640 cannot be divided by just 1 and 8,675,640, it is not a prime number.