The number 3,333,330 can be evenly divided by 1 2 3 5 6 7 9 10 11 13 14 15 18 21 22 26 30 33 35 37 39 42 45 55 63 65 66 70 74 77 78 90 91 99 105 110 111 117 126 130 143 154 165 182 185 195 198 210 222 231 234 259 273 286 315 330 333 370 385 390 407 429 455 462 481 495 518 546 555 585 630 666 693 715 770 777 814 819 858 910 962 990 1,001 1,110 1,155 1,170 1,221 1,287 1,295 1,365 1,386 1,430 1,443 1,554 1,638 1,665 2,002 2,035 2,145 2,310 2,331 2,405 2,442 2,574 2,590 2,730 2,849 2,886 3,003 3,330 3,367 3,465 3,663 3,885 4,070 4,095 4,290 4,329 4,662 4,810 5,005 5,291 5,698 6,006 6,105 6,435 6,734 6,930 7,215 7,326 7,770 8,190 8,547 8,658 9,009 10,010 10,101 10,582 11,655 12,210 12,870 14,245 14,430 15,015 15,873 16,835 17,094 18,018 18,315 20,202 21,645 23,310 25,641 26,455 28,490 30,030 30,303 31,746 33,670 36,630 37,037 42,735 43,290 45,045 47,619 50,505 51,282 52,910 60,606 74,074 79,365 85,470 90,090 95,238 101,010 111,111 128,205 151,515 158,730 185,185 222,222 238,095 256,410 303,030 333,333 370,370 476,190 555,555 666,666 1,111,110 1,666,665 and 3,333,330, with no remainder.
Since 3,333,330 cannot be divided by just 1 and 3,333,330, it is a composite number.