The number 2,431,800 can be evenly divided by 1 2 3 4 5 6 7 8 9 10 12 14 15 18 20 21 24 25 28 30 35 36 40 42 45 50 56 60 63 70 72 75 84 90 100 105 120 126 140 150 168 175 180 193 200 210 225 252 280 300 315 350 360 386 420 450 504 525 579 600 630 700 772 840 900 965 1,050 1,158 1,260 1,351 1,400 1,544 1,575 1,737 1,800 1,930 2,100 2,316 2,520 2,702 2,895 3,150 3,474 3,860 4,053 4,200 4,632 4,825 5,404 5,790 6,300 6,755 6,948 7,720 8,106 8,685 9,650 10,808 11,580 12,159 12,600 13,510 13,896 14,475 16,212 17,370 19,300 20,265 23,160 24,318 27,020 28,950 32,424 33,775 34,740 38,600 40,530 43,425 48,636 54,040 57,900 60,795 67,550 69,480 81,060 86,850 97,272 101,325 115,800 121,590 135,100 162,120 173,700 202,650 243,180 270,200 303,975 347,400 405,300 486,360 607,950 810,600 1,215,900 and 2,431,800, with no remainder.
Since 2,431,800 cannot be divided by just 1 and 2,431,800, it is a composite number.