The number 688,800 can be evenly divided by 1 2 3 4 5 6 7 8 10 12 14 15 16 20 21 24 25 28 30 32 35 40 41 42 48 50 56 60 70 75 80 82 84 96 100 105 112 120 123 140 150 160 164 168 175 200 205 210 224 240 246 280 287 300 328 336 350 400 410 420 480 492 525 560 574 600 615 656 672 700 800 820 840 861 984 1,025 1,050 1,120 1,148 1,200 1,230 1,312 1,400 1,435 1,640 1,680 1,722 1,968 2,050 2,100 2,296 2,400 2,460 2,800 2,870 3,075 3,280 3,360 3,444 3,936 4,100 4,200 4,305 4,592 4,920 5,600 5,740 6,150 6,560 6,888 7,175 8,200 8,400 8,610 9,184 9,840 11,480 12,300 13,776 14,350 16,400 16,800 17,220 19,680 21,525 22,960 24,600 27,552 28,700 32,800 34,440 43,050 45,920 49,200 57,400 68,880 86,100 98,400 114,800 137,760 172,200 229,600 344,400 and 688,800, with no remainder.
Since 688,800 cannot be divided by just 1 and 688,800, it is a composite number.