A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3204036 can be evenly divided by 1 2 3 4 6 9 11 12 18 22 27 29 31 33 36 44 54 58 62 66 81 87 93 99 108 116 124 132 162 174 186 198 261 279 297 319 324 341 348 372 396 522 558 594 638 682 783 837 891 899 957 1,023 1,044 1,116 1,188 1,276 1,364 1,566 1,674 1,782 1,798 1,914 2,046 2,349 2,511 2,697 2,871 3,069 3,132 3,348 3,564 3,596 3,828 4,092 4,698 5,022 5,394 5,742 6,138 8,091 8,613 9,207 9,396 9,889 10,044 10,788 11,484 12,276 16,182 17,226 18,414 19,778 24,273 25,839 27,621 29,667 32,364 34,452 36,828 39,556 48,546 51,678 55,242 59,334 72,819 89,001 97,092 103,356 110,484 118,668 145,638 178,002 267,003 291,276 356,004 534,006 801,009 1,068,012 1,602,018 and 3,204,036, with no remainder.
Since 3,204,036 cannot be divided by just 1 and 3,204,036, it is not a prime number.