A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3713616 can be evenly divided by 1 2 3 4 6 8 9 12 16 17 18 24 34 36 37 41 48 51 68 72 74 82 102 111 123 136 144 148 153 164 204 222 246 272 296 306 328 333 369 408 444 492 592 612 629 656 666 697 738 816 888 984 1,224 1,258 1,332 1,394 1,476 1,517 1,776 1,887 1,968 2,091 2,448 2,516 2,664 2,788 2,952 3,034 3,774 4,182 4,551 5,032 5,328 5,576 5,661 5,904 6,068 6,273 7,548 8,364 9,102 10,064 11,152 11,322 12,136 12,546 13,653 15,096 16,728 18,204 22,644 24,272 25,092 25,789 27,306 30,192 33,456 36,408 45,288 50,184 51,578 54,612 72,816 77,367 90,576 100,368 103,156 109,224 154,734 206,312 218,448 232,101 309,468 412,624 464,202 618,936 928,404 1,237,872 1,856,808 and 3,713,616, with no remainder.
Since 3,713,616 cannot be divided by just 1 and 3,713,616, it is not a prime number.