The number 3,126,600 can be evenly divided by 1 2 3 4 5 6 8 9 10 12 15 18 20 24 25 27 30 36 40 45 50 54 60 72 75 81 90 100 108 120 135 150 162 180 193 200 216 225 270 300 324 360 386 405 450 540 579 600 648 675 772 810 900 965 1,080 1,158 1,350 1,544 1,620 1,737 1,800 1,930 2,025 2,316 2,700 2,895 3,240 3,474 3,860 4,050 4,632 4,825 5,211 5,400 5,790 6,948 7,720 8,100 8,685 9,650 10,422 11,580 13,896 14,475 15,633 16,200 17,370 19,300 20,844 23,160 26,055 28,950 31,266 34,740 38,600 41,688 43,425 52,110 57,900 62,532 69,480 78,165 86,850 104,220 115,800 125,064 130,275 156,330 173,700 208,440 260,550 312,660 347,400 390,825 521,100 625,320 781,650 1,042,200 1,563,300 and 3,126,600, with no remainder.
Since 3,126,600 cannot be divided by just 1 and 3,126,600, it is a composite number.