A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 8873388 can be evenly divided by 1 2 3 4 6 9 12 17 18 27 34 36 51 54 68 81 102 108 153 162 179 204 243 306 324 358 459 486 537 612 716 729 918 972 1,074 1,377 1,458 1,611 1,836 2,148 2,754 2,916 3,043 3,222 4,131 4,833 5,508 6,086 6,444 8,262 9,129 9,666 12,172 12,393 14,499 16,524 18,258 19,332 24,786 27,387 28,998 36,516 43,497 49,572 54,774 57,996 82,161 86,994 109,548 130,491 164,322 173,988 246,483 260,982 328,644 492,966 521,964 739,449 985,932 1,478,898 2,218,347 2,957,796 4,436,694 and 8,873,388, with no remainder.
Since 8,873,388 cannot be divided by just 1 and 8,873,388, it is not a prime number.