A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3519516 can be evenly divided by 1 2 3 4 6 7 11 12 13 14 21 22 26 28 33 39 42 44 52 66 77 78 84 91 132 143 154 156 182 231 273 286 293 308 364 429 462 546 572 586 858 879 924 1,001 1,092 1,172 1,716 1,758 2,002 2,051 3,003 3,223 3,516 3,809 4,004 4,102 6,006 6,153 6,446 7,618 8,204 9,669 11,427 12,012 12,306 12,892 15,236 19,338 22,561 22,854 24,612 26,663 38,676 41,899 45,122 45,708 53,326 67,683 79,989 83,798 90,244 106,652 125,697 135,366 159,978 167,596 251,394 270,732 293,293 319,956 502,788 586,586 879,879 1,173,172 1,759,758 and 3,519,516, with no remainder.
Since 3,519,516 cannot be divided by just 1 and 3,519,516, it is not a prime number.