The number 1,255,824 can be evenly divided by 1 2 3 4 6 8 9 12 16 17 18 19 24 27 34 36 38 48 51 54 57 68 72 76 81 102 108 114 136 144 152 153 162 171 204 216 228 243 272 304 306 323 324 342 408 432 456 459 486 513 612 646 648 684 816 912 918 969 972 1,026 1,224 1,292 1,296 1,368 1,377 1,539 1,836 1,938 1,944 2,052 2,448 2,584 2,736 2,754 2,907 3,078 3,672 3,876 3,888 4,104 4,131 4,617 5,168 5,508 5,814 6,156 7,344 7,752 8,208 8,262 8,721 9,234 11,016 11,628 12,312 15,504 16,524 17,442 18,468 22,032 23,256 24,624 26,163 33,048 34,884 36,936 46,512 52,326 66,096 69,768 73,872 78,489 104,652 139,536 156,978 209,304 313,956 418,608 627,912 and 1,255,824, with no remainder.
Since 1,255,824 cannot be divided by just 1 and 1,255,824, it is a composite number.