The number 4,066,608 can be evenly divided by 1 2 3 4 6 7 8 12 13 14 16 19 21 24 26 28 38 39 42 48 49 52 56 57 76 78 84 91 98 104 112 114 133 147 152 156 168 182 196 208 228 247 266 273 294 304 312 336 343 364 392 399 456 494 532 546 588 624 637 686 728 741 784 798 912 931 988 1,029 1,064 1,092 1,176 1,274 1,372 1,456 1,482 1,596 1,729 1,862 1,911 1,976 2,058 2,128 2,184 2,352 2,548 2,744 2,793 2,964 3,192 3,458 3,724 3,822 3,952 4,116 4,368 4,459 5,096 5,187 5,488 5,586 5,928 6,384 6,517 6,916 7,448 7,644 8,232 8,918 10,192 10,374 11,172 11,856 12,103 13,034 13,377 13,832 14,896 15,288 16,464 17,836 19,551 20,748 22,344 24,206 26,068 26,754 27,664 30,576 35,672 36,309 39,102 41,496 44,688 48,412 52,136 53,508 71,344 72,618 78,204 82,992 84,721 96,824 104,272 107,016 145,236 156,408 169,442 193,648 214,032 254,163 290,472 312,816 338,884 508,326 580,944 677,768 1,016,652 1,355,536 2,033,304 and 4,066,608, with no remainder.
Since 4,066,608 cannot be divided by just 1 and 4,066,608, it is a composite number.