The number 1,100,400 can be evenly divided by 1 2 3 4 5 6 7 8 10 12 14 15 16 20 21 24 25 28 30 35 40 42 48 50 56 60 70 75 80 84 100 105 112 120 131 140 150 168 175 200 210 240 262 280 300 336 350 393 400 420 524 525 560 600 655 700 786 840 917 1,048 1,050 1,200 1,310 1,400 1,572 1,680 1,834 1,965 2,096 2,100 2,620 2,751 2,800 3,144 3,275 3,668 3,930 4,200 4,585 5,240 5,502 6,288 6,550 7,336 7,860 8,400 9,170 9,825 10,480 11,004 13,100 13,755 14,672 15,720 18,340 19,650 22,008 22,925 26,200 27,510 31,440 36,680 39,300 44,016 45,850 52,400 55,020 68,775 73,360 78,600 91,700 110,040 137,550 157,200 183,400 220,080 275,100 366,800 550,200 and 1,100,400, with no remainder.
Since 1,100,400 cannot be divided by just 1 and 1,100,400, it is a composite number.