The number 2,188,620 can be evenly divided by 1 2 3 4 5 6 7 9 10 12 14 15 18 20 21 27 28 30 35 36 42 45 54 60 63 70 81 84 90 105 108 126 135 140 162 180 189 193 210 252 270 315 324 378 386 405 420 540 567 579 630 756 772 810 945 965 1,134 1,158 1,260 1,351 1,620 1,737 1,890 1,930 2,268 2,316 2,702 2,835 2,895 3,474 3,780 3,860 4,053 5,211 5,404 5,670 5,790 6,755 6,948 8,106 8,685 10,422 11,340 11,580 12,159 13,510 15,633 16,212 17,370 20,265 20,844 24,318 26,055 27,020 31,266 34,740 36,477 40,530 48,636 52,110 60,795 62,532 72,954 78,165 81,060 104,220 109,431 121,590 145,908 156,330 182,385 218,862 243,180 312,660 364,770 437,724 547,155 729,540 1,094,310 and 2,188,620, with no remainder.
Since 2,188,620 cannot be divided by just 1 and 2,188,620, it is a composite number.