A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 8705268 can be evenly divided by 1 2 3 4 6 9 11 12 13 18 19 22 26 33 36 38 39 44 52 57 66 76 78 89 99 114 117 132 143 156 171 178 198 209 228 234 247 267 286 342 356 396 418 429 468 494 534 572 627 684 741 801 836 858 979 988 1,068 1,157 1,254 1,287 1,482 1,602 1,691 1,716 1,881 1,958 2,223 2,314 2,508 2,574 2,717 2,937 2,964 3,204 3,382 3,471 3,762 3,916 4,446 4,628 5,073 5,148 5,434 5,874 6,764 6,942 7,524 8,151 8,811 8,892 10,146 10,413 10,868 11,748 12,727 13,884 15,219 16,302 17,622 18,601 20,292 20,826 21,983 24,453 25,454 30,438 32,604 35,244 37,202 38,181 41,652 43,966 48,906 50,908 55,803 60,876 65,949 74,404 76,362 87,932 97,812 111,606 114,543 131,898 152,724 167,409 197,847 223,212 229,086 241,813 263,796 334,818 395,694 458,172 483,626 669,636 725,439 791,388 967,252 1,450,878 2,176,317 2,901,756 4,352,634 and 8,705,268, with no remainder.
Since 8,705,268 cannot be divided by just 1 and 8,705,268, it is not a prime number.