The number 631,800 can be evenly divided by 1 2 3 4 5 6 8 9 10 12 13 15 18 20 24 25 26 27 30 36 39 40 45 50 52 54 60 65 72 75 78 81 90 100 104 108 117 120 130 135 150 156 162 180 195 200 216 225 234 243 260 270 300 312 324 325 351 360 390 405 450 468 486 520 540 585 600 648 650 675 702 780 810 900 936 972 975 1,053 1,080 1,170 1,215 1,300 1,350 1,404 1,560 1,620 1,755 1,800 1,944 1,950 2,025 2,106 2,340 2,430 2,600 2,700 2,808 2,925 3,159 3,240 3,510 3,900 4,050 4,212 4,680 4,860 5,265 5,400 5,850 6,075 6,318 7,020 7,800 8,100 8,424 8,775 9,720 10,530 11,700 12,150 12,636 14,040 15,795 16,200 17,550 21,060 23,400 24,300 25,272 26,325 31,590 35,100 42,120 48,600 52,650 63,180 70,200 78,975 105,300 126,360 157,950 210,600 315,900 and 631,800, with no remainder.
Since 631,800 cannot be divided by just 1 and 631,800, it is a composite number.