A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3338664 can be evenly divided by 1 2 3 4 6 7 8 12 14 17 21 24 28 34 42 49 51 56 68 84 98 102 119 136 147 167 168 196 204 238 294 334 357 392 408 476 501 588 668 714 833 952 1,002 1,169 1,176 1,336 1,428 1,666 2,004 2,338 2,499 2,839 2,856 3,332 3,507 4,008 4,676 4,998 5,678 6,664 7,014 8,183 8,517 9,352 9,996 11,356 14,028 16,366 17,034 19,873 19,992 22,712 24,549 28,056 32,732 34,068 39,746 49,098 59,619 65,464 68,136 79,492 98,196 119,238 139,111 158,984 196,392 238,476 278,222 417,333 476,952 556,444 834,666 1,112,888 1,669,332 and 3,338,664, with no remainder.
Since 3,338,664 cannot be divided by just 1 and 3,338,664, it is not a prime number.