A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 2174436 can be evenly divided by 1 2 3 4 6 9 11 12 17 18 19 22 33 34 36 38 44 51 57 66 68 76 99 102 114 132 153 171 187 198 204 209 228 289 306 323 342 374 396 418 561 578 612 627 646 684 748 836 867 969 1,122 1,156 1,254 1,292 1,683 1,734 1,881 1,938 2,244 2,508 2,601 2,907 3,179 3,366 3,468 3,553 3,762 3,876 5,202 5,491 5,814 6,358 6,732 7,106 7,524 9,537 10,404 10,659 10,982 11,628 12,716 14,212 16,473 19,074 21,318 21,964 28,611 31,977 32,946 38,148 42,636 49,419 57,222 60,401 63,954 65,892 98,838 114,444 120,802 127,908 181,203 197,676 241,604 362,406 543,609 724,812 1,087,218 and 2,174,436, with no remainder.
Since 2,174,436 cannot be divided by just 1 and 2,174,436, it is not a prime number.