A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3096720 can be evenly divided by 1 2 3 4 5 6 8 9 10 11 12 15 16 17 18 20 22 23 24 30 33 34 36 40 44 45 46 48 51 55 60 66 68 69 72 80 85 88 90 92 99 102 110 115 120 132 136 138 144 153 165 170 176 180 184 187 198 204 207 220 230 240 253 255 264 272 276 306 330 340 345 360 368 374 391 396 408 414 440 460 495 506 510 528 552 561 612 660 680 690 720 748 759 765 782 792 816 828 880 920 935 990 1,012 1,020 1,035 1,104 1,122 1,173 1,224 1,265 1,320 1,360 1,380 1,496 1,518 1,530 1,564 1,584 1,656 1,683 1,840 1,870 1,955 1,980 2,024 2,040 2,070 2,244 2,277 2,346 2,448 2,530 2,640 2,760 2,805 2,992 3,036 3,060 3,128 3,312 3,366 3,519 3,740 3,795 3,910 3,960 4,048 4,080 4,140 4,301 4,488 4,554 4,692 5,060 5,520 5,610 5,865 6,072 6,120 6,256 6,732 7,038 7,480 7,590 7,820 7,920 8,280 8,415 8,602 8,976 9,108 9,384 10,120 11,220 11,385 11,730 12,144 12,240 12,903 13,464 14,076 14,960 15,180 15,640 16,560 16,830 17,204 17,595 18,216 18,768 20,240 21,505 22,440 22,770 23,460 25,806 26,928 28,152 30,360 31,280 33,660 34,408 35,190 36,432 38,709 43,010 44,880 45,540 46,920 51,612 56,304 60,720 64,515 67,320 68,816 70,380 77,418 86,020 91,080 93,840 103,224 129,030 134,640 140,760 154,836 172,040 182,160 193,545 206,448 258,060 281,520 309,672 344,080 387,090 516,120 619,344 774,180 1,032,240 1,548,360 and 3,096,720, with no remainder.
Since 3,096,720 cannot be divided by just 1 and 3,096,720, it is not a prime number.