A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3316320 can be evenly divided by 1 2 3 4 5 6 7 8 9 10 12 14 15 16 18 20 21 24 28 30 32 35 36 40 42 45 47 48 49 56 60 63 70 72 80 84 90 94 96 98 105 112 120 126 140 141 144 147 160 168 180 188 196 210 224 235 240 245 252 280 282 288 294 315 329 336 360 376 392 420 423 441 470 480 490 504 560 564 588 630 658 672 705 720 735 752 784 840 846 882 940 980 987 1,008 1,120 1,128 1,176 1,260 1,316 1,410 1,440 1,470 1,504 1,568 1,645 1,680 1,692 1,764 1,880 1,960 1,974 2,016 2,115 2,205 2,256 2,303 2,352 2,520 2,632 2,820 2,940 2,961 3,290 3,360 3,384 3,528 3,760 3,920 3,948 4,230 4,410 4,512 4,606 4,704 4,935 5,040 5,264 5,640 5,880 5,922 6,580 6,768 6,909 7,056 7,520 7,840 7,896 8,460 8,820 9,212 9,870 10,080 10,528 11,280 11,515 11,760 11,844 13,160 13,536 13,818 14,112 14,805 15,792 16,920 17,640 18,424 19,740 20,727 22,560 23,030 23,520 23,688 26,320 27,636 29,610 31,584 33,840 34,545 35,280 36,848 39,480 41,454 46,060 47,376 52,640 55,272 59,220 67,680 69,090 70,560 73,696 78,960 82,908 92,120 94,752 103,635 110,544 118,440 138,180 157,920 165,816 184,240 207,270 221,088 236,880 276,360 331,632 368,480 414,540 473,760 552,720 663,264 829,080 1,105,440 1,658,160 and 3,316,320, with no remainder.
Since 3,316,320 cannot be divided by just 1 and 3,316,320, it is not a prime number.