The number 624,240 can be evenly divided by 1 2 3 4 5 6 8 9 10 12 15 16 17 18 20 24 27 30 34 36 40 45 48 51 54 60 68 72 80 85 90 102 108 120 135 136 144 153 170 180 204 216 240 255 270 272 289 306 340 360 408 432 459 510 540 578 612 680 720 765 816 867 918 1,020 1,080 1,156 1,224 1,360 1,445 1,530 1,734 1,836 2,040 2,160 2,295 2,312 2,448 2,601 2,890 3,060 3,468 3,672 4,080 4,335 4,590 4,624 5,202 5,780 6,120 6,936 7,344 7,803 8,670 9,180 10,404 11,560 12,240 13,005 13,872 15,606 17,340 18,360 20,808 23,120 26,010 31,212 34,680 36,720 39,015 41,616 52,020 62,424 69,360 78,030 104,040 124,848 156,060 208,080 312,120 and 624,240, with no remainder.
Since 624,240 cannot be divided by just 1 and 624,240, it is a composite number.