A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 8168600 can be evenly divided by 1 2 4 5 8 10 11 20 22 25 40 44 47 50 55 79 88 94 100 110 158 188 200 220 235 275 316 376 395 440 470 517 550 632 790 869 940 1,034 1,100 1,175 1,580 1,738 1,880 1,975 2,068 2,200 2,350 2,585 3,160 3,476 3,713 3,950 4,136 4,345 4,700 5,170 6,952 7,426 7,900 8,690 9,400 10,340 12,925 14,852 15,800 17,380 18,565 20,680 21,725 25,850 29,704 34,760 37,130 40,843 43,450 51,700 74,260 81,686 86,900 92,825 103,400 148,520 163,372 173,800 185,650 204,215 326,744 371,300 408,430 742,600 816,860 1,021,075 1,633,720 2,042,150 4,084,300 and 8,168,600, with no remainder.
Since 8,168,600 cannot be divided by just 1 and 8,168,600, it is not a prime number.