A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3214224 can be evenly divided by 1 2 3 4 6 8 9 12 13 16 17 18 24 26 34 36 39 48 51 52 68 72 78 101 102 104 117 136 144 153 156 202 204 208 221 234 272 303 306 312 404 408 442 468 606 612 624 663 808 816 884 909 936 1,212 1,224 1,313 1,326 1,616 1,717 1,768 1,818 1,872 1,989 2,424 2,448 2,626 2,652 3,434 3,536 3,636 3,939 3,978 4,848 5,151 5,252 5,304 6,868 7,272 7,878 7,956 10,302 10,504 10,608 11,817 13,736 14,544 15,453 15,756 15,912 20,604 21,008 22,321 23,634 27,472 30,906 31,512 31,824 41,208 44,642 47,268 61,812 63,024 66,963 82,416 89,284 94,536 123,624 133,926 178,568 189,072 200,889 247,248 267,852 357,136 401,778 535,704 803,556 1,071,408 1,607,112 and 3,214,224, with no remainder.
Since 3,214,224 cannot be divided by just 1 and 3,214,224, it is not a prime number.