The number 1,626,240 can be evenly divided by 1 2 3 4 5 6 7 8 10 11 12 14 15 16 20 21 22 24 28 30 32 33 35 40 42 44 48 55 56 60 64 66 70 77 80 84 88 96 105 110 112 120 121 128 132 140 154 160 165 168 176 192 210 220 224 231 240 242 264 280 308 320 330 336 352 363 384 385 420 440 448 462 480 484 528 560 605 616 640 660 672 704 726 770 840 847 880 896 924 960 968 1,056 1,120 1,155 1,210 1,232 1,320 1,344 1,408 1,452 1,540 1,680 1,694 1,760 1,815 1,848 1,920 1,936 2,112 2,240 2,310 2,420 2,464 2,541 2,640 2,688 2,904 3,080 3,360 3,388 3,520 3,630 3,696 3,872 4,224 4,235 4,480 4,620 4,840 4,928 5,082 5,280 5,808 6,160 6,720 6,776 7,040 7,260 7,392 7,744 8,470 9,240 9,680 9,856 10,164 10,560 11,616 12,320 12,705 13,440 13,552 14,520 14,784 15,488 16,940 18,480 19,360 20,328 21,120 23,232 24,640 25,410 27,104 29,040 29,568 33,880 36,960 38,720 40,656 46,464 49,280 50,820 54,208 58,080 67,760 73,920 77,440 81,312 101,640 108,416 116,160 135,520 147,840 162,624 203,280 232,320 271,040 325,248 406,560 542,080 813,120 and 1,626,240, with no remainder.
Since 1,626,240 cannot be divided by just 1 and 1,626,240, it is a composite number.