A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3288480 can be evenly divided by 1 2 3 4 5 6 8 10 12 13 15 16 17 20 24 26 30 31 32 34 39 40 48 51 52 60 62 65 68 78 80 85 93 96 102 104 120 124 130 136 155 156 160 170 186 195 204 208 221 240 248 255 260 272 310 312 340 372 390 403 408 416 442 465 480 496 510 520 527 544 620 624 663 680 744 780 806 816 884 930 992 1,020 1,040 1,054 1,105 1,209 1,240 1,248 1,326 1,360 1,488 1,560 1,581 1,612 1,632 1,768 1,860 2,015 2,040 2,080 2,108 2,210 2,418 2,480 2,635 2,652 2,720 2,976 3,120 3,162 3,224 3,315 3,536 3,720 4,030 4,080 4,216 4,420 4,836 4,960 5,270 5,304 6,045 6,240 6,324 6,448 6,630 6,851 7,072 7,440 7,905 8,060 8,160 8,432 8,840 9,672 10,540 10,608 12,090 12,648 12,896 13,260 13,702 14,880 15,810 16,120 16,864 17,680 19,344 20,553 21,080 21,216 24,180 25,296 26,520 27,404 31,620 32,240 34,255 35,360 38,688 41,106 42,160 48,360 50,592 53,040 54,808 63,240 64,480 68,510 82,212 84,320 96,720 102,765 106,080 109,616 126,480 137,020 164,424 193,440 205,530 219,232 252,960 274,040 328,848 411,060 548,080 657,696 822,120 1,096,160 1,644,240 and 3,288,480, with no remainder.
Since 3,288,480 cannot be divided by just 1 and 3,288,480, it is not a prime number.