The number 3,655,680 can be evenly divided by 1 2 3 4 5 6 7 8 10 12 14 15 16 17 20 21 24 28 30 32 34 35 40 42 48 51 56 60 64 68 70 80 84 85 96 102 105 112 119 120 128 136 140 160 168 170 192 204 210 224 238 240 255 256 272 280 320 336 340 357 384 408 420 448 476 480 510 512 544 560 595 640 672 680 714 768 816 840 896 952 960 1,020 1,024 1,088 1,120 1,190 1,280 1,344 1,360 1,428 1,536 1,632 1,680 1,785 1,792 1,904 1,920 2,040 2,048 2,176 2,240 2,380 2,560 2,688 2,720 2,856 3,072 3,264 3,360 3,570 3,584 3,808 3,840 4,080 4,352 4,480 4,760 5,120 5,376 5,440 5,712 6,144 6,528 6,720 7,140 7,168 7,616 7,680 8,160 8,704 8,960 9,520 10,240 10,752 10,880 11,424 13,056 13,440 14,280 14,336 15,232 15,360 16,320 17,408 17,920 19,040 21,504 21,760 22,848 26,112 26,880 28,560 30,464 30,720 32,640 34,816 35,840 38,080 43,008 43,520 45,696 52,224 53,760 57,120 60,928 65,280 71,680 76,160 87,040 91,392 104,448 107,520 114,240 121,856 130,560 152,320 174,080 182,784 215,040 228,480 243,712 261,120 304,640 365,568 456,960 522,240 609,280 731,136 913,920 1,218,560 1,827,840 and 3,655,680, with no remainder.
Since 3,655,680 cannot be divided by just 1 and 3,655,680, it is a composite number.