A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 267960 can be evenly divided by 1 2 3 4 5 6 7 8 10 11 12 14 15 20 21 22 24 28 29 30 33 35 40 42 44 55 56 58 60 66 70 77 84 87 88 105 110 116 120 132 140 145 154 165 168 174 203 210 220 231 232 264 280 290 308 319 330 348 385 406 420 435 440 462 580 609 616 638 660 696 770 812 840 870 924 957 1,015 1,155 1,160 1,218 1,276 1,320 1,540 1,595 1,624 1,740 1,848 1,914 2,030 2,233 2,310 2,436 2,552 3,045 3,080 3,190 3,480 3,828 4,060 4,466 4,620 4,785 4,872 6,090 6,380 6,699 7,656 8,120 8,932 9,240 9,570 11,165 12,180 12,760 13,398 17,864 19,140 22,330 24,360 26,796 33,495 38,280 44,660 53,592 66,990 89,320 133,980 and 267,960, with no remainder.
Since 267,960 cannot be divided by just 1 and 267,960, it is not a prime number.