The number 1,439,640 can be evenly divided by 1 2 3 4 5 6 8 9 10 12 15 18 20 24 27 30 31 36 40 43 45 54 60 62 72 86 90 93 108 120 124 129 135 155 172 180 186 215 216 248 258 270 279 310 344 360 372 387 430 465 516 540 558 620 645 744 774 837 860 930 1,032 1,080 1,116 1,161 1,240 1,290 1,333 1,395 1,548 1,674 1,720 1,860 1,935 2,232 2,322 2,580 2,666 2,790 3,096 3,348 3,720 3,870 3,999 4,185 4,644 5,160 5,332 5,580 5,805 6,665 6,696 7,740 7,998 8,370 9,288 10,664 11,160 11,610 11,997 13,330 15,480 15,996 16,740 19,995 23,220 23,994 26,660 31,992 33,480 35,991 39,990 46,440 47,988 53,320 59,985 71,982 79,980 95,976 119,970 143,964 159,960 179,955 239,940 287,928 359,910 479,880 719,820 and 1,439,640, with no remainder.
Since 1,439,640 cannot be divided by just 1 and 1,439,640, it is a composite number.