The number 1,259,280 can be evenly divided by 1 2 3 4 5 6 8 9 10 11 12 15 16 18 20 22 24 27 30 33 36 40 44 45 48 53 54 55 60 66 72 80 88 90 99 106 108 110 120 132 135 144 159 165 176 180 198 212 216 220 240 264 265 270 297 318 330 360 396 424 432 440 477 495 528 530 540 583 594 636 660 720 792 795 848 880 954 990 1,060 1,080 1,166 1,188 1,272 1,320 1,431 1,485 1,584 1,590 1,749 1,908 1,980 2,120 2,160 2,332 2,376 2,385 2,544 2,640 2,862 2,915 2,970 3,180 3,498 3,816 3,960 4,240 4,664 4,752 4,770 5,247 5,724 5,830 5,940 6,360 6,996 7,155 7,632 7,920 8,745 9,328 9,540 10,494 11,448 11,660 11,880 12,720 13,992 14,310 15,741 17,490 19,080 20,988 22,896 23,320 23,760 26,235 27,984 28,620 31,482 34,980 38,160 41,976 46,640 52,470 57,240 62,964 69,960 78,705 83,952 104,940 114,480 125,928 139,920 157,410 209,880 251,856 314,820 419,760 629,640 and 1,259,280, with no remainder.
Since 1,259,280 cannot be divided by just 1 and 1,259,280, it is a composite number.