The number 1,399,320 can be evenly divided by 1 2 3 4 5 6 8 9 10 12 13 15 18 20 23 24 26 30 36 39 40 45 46 52 60 65 69 72 78 90 92 104 115 117 120 130 138 156 169 180 184 195 207 230 234 260 276 299 312 338 345 360 390 414 460 468 507 520 552 585 598 676 690 780 828 845 897 920 936 1,014 1,035 1,170 1,196 1,352 1,380 1,495 1,521 1,560 1,656 1,690 1,794 2,028 2,070 2,340 2,392 2,535 2,691 2,760 2,990 3,042 3,380 3,588 3,887 4,056 4,140 4,485 4,680 5,070 5,382 5,980 6,084 6,760 7,176 7,605 7,774 8,280 8,970 10,140 10,764 11,661 11,960 12,168 13,455 15,210 15,548 17,940 19,435 20,280 21,528 23,322 26,910 30,420 31,096 34,983 35,880 38,870 46,644 53,820 58,305 60,840 69,966 77,740 93,288 107,640 116,610 139,932 155,480 174,915 233,220 279,864 349,830 466,440 699,660 and 1,399,320, with no remainder.
Since 1,399,320 cannot be divided by just 1 and 1,399,320, it is a composite number.