A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1616112 can be evenly divided by 1 2 3 4 6 8 9 12 16 18 24 27 29 36 43 48 54 58 72 81 86 87 108 116 129 144 162 172 174 216 232 258 261 324 344 348 387 432 464 516 522 648 688 696 774 783 1,032 1,044 1,161 1,247 1,296 1,392 1,548 1,566 2,064 2,088 2,322 2,349 2,494 3,096 3,132 3,483 3,741 4,176 4,644 4,698 4,988 6,192 6,264 6,966 7,482 9,288 9,396 9,976 11,223 12,528 13,932 14,964 18,576 18,792 19,952 22,446 27,864 29,928 33,669 37,584 44,892 55,728 59,856 67,338 89,784 101,007 134,676 179,568 202,014 269,352 404,028 538,704 808,056 and 1,616,112, with no remainder.
Since 1,616,112 cannot be divided by just 1 and 1,616,112, it is not a prime number.