A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 6808158 can be evenly divided by 1 2 3 6 7 9 14 18 21 27 31 42 49 54 62 63 83 93 98 126 147 166 186 189 217 249 279 294 378 434 441 498 558 581 651 747 837 882 1,162 1,302 1,323 1,494 1,519 1,674 1,743 1,953 2,241 2,573 2,646 3,038 3,486 3,906 4,067 4,482 4,557 5,146 5,229 5,859 7,719 8,134 9,114 10,458 11,718 12,201 13,671 15,438 15,687 18,011 23,157 24,402 27,342 31,374 36,022 36,603 41,013 46,314 54,033 69,471 73,206 82,026 108,066 109,809 126,077 138,942 162,099 219,618 252,154 324,198 378,231 486,297 756,462 972,594 1,134,693 2,269,386 3,404,079 and 6,808,158, with no remainder.
Since 6,808,158 cannot be divided by just 1 and 6,808,158, it is not a prime number.