A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3687264 can be evenly divided by 1 2 3 4 6 7 8 9 12 14 16 18 21 24 28 31 32 36 42 48 56 59 62 63 72 84 93 96 112 118 124 126 144 168 177 186 217 224 236 248 252 279 288 336 354 372 413 434 472 496 504 531 558 651 672 708 744 826 868 944 992 1,008 1,062 1,116 1,239 1,302 1,416 1,488 1,652 1,736 1,829 1,888 1,953 2,016 2,124 2,232 2,478 2,604 2,832 2,976 3,304 3,472 3,658 3,717 3,906 4,248 4,464 4,956 5,208 5,487 5,664 6,608 6,944 7,316 7,434 7,812 8,496 8,928 9,912 10,416 10,974 12,803 13,216 14,632 14,868 15,624 16,461 16,992 19,824 20,832 21,948 25,606 29,264 29,736 31,248 32,922 38,409 39,648 43,896 51,212 58,528 59,472 62,496 65,844 76,818 87,792 102,424 115,227 118,944 131,688 153,636 175,584 204,848 230,454 263,376 307,272 409,696 460,908 526,752 614,544 921,816 1,229,088 1,843,632 and 3,687,264, with no remainder.
Since 3,687,264 cannot be divided by just 1 and 3,687,264, it is not a prime number.