A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1273680 can be evenly divided by 1 2 3 4 5 6 8 9 10 12 15 16 18 20 24 29 30 36 40 45 48 58 60 61 72 80 87 90 116 120 122 144 145 174 180 183 232 240 244 261 290 305 348 360 366 435 464 488 522 549 580 610 696 720 732 870 915 976 1,044 1,098 1,160 1,220 1,305 1,392 1,464 1,740 1,769 1,830 2,088 2,196 2,320 2,440 2,610 2,745 2,928 3,480 3,538 3,660 4,176 4,392 4,880 5,220 5,307 5,490 6,960 7,076 7,320 8,784 8,845 10,440 10,614 10,980 14,152 14,640 15,921 17,690 20,880 21,228 21,960 26,535 28,304 31,842 35,380 42,456 43,920 53,070 63,684 70,760 79,605 84,912 106,140 127,368 141,520 159,210 212,280 254,736 318,420 424,560 636,840 and 1,273,680, with no remainder.
Since 1,273,680 cannot be divided by just 1 and 1,273,680, it is not a prime number.