A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3361344 can be evenly divided by 1 2 3 4 6 7 8 12 14 16 21 24 28 32 41 42 48 56 61 64 82 84 96 112 122 123 164 168 183 192 224 244 246 287 328 336 366 427 448 488 492 574 656 672 732 854 861 976 984 1,148 1,281 1,312 1,344 1,464 1,708 1,722 1,952 1,968 2,296 2,501 2,562 2,624 2,928 3,416 3,444 3,904 3,936 4,592 5,002 5,124 5,856 6,832 6,888 7,503 7,872 9,184 10,004 10,248 11,712 13,664 13,776 15,006 17,507 18,368 20,008 20,496 27,328 27,552 30,012 35,014 40,016 40,992 52,521 55,104 60,024 70,028 80,032 81,984 105,042 120,048 140,056 160,064 210,084 240,096 280,112 420,168 480,192 560,224 840,336 1,120,448 1,680,672 and 3,361,344, with no remainder.
Since 3,361,344 cannot be divided by just 1 and 3,361,344, it is not a prime number.