A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1419912 can be evenly divided by 1 2 3 4 6 8 9 12 13 18 24 26 36 37 39 41 52 72 74 78 82 104 111 117 123 148 156 164 222 234 246 296 312 328 333 369 444 468 481 492 533 666 738 888 936 962 984 1,066 1,332 1,443 1,476 1,517 1,599 1,924 2,132 2,664 2,886 2,952 3,034 3,198 3,848 4,264 4,329 4,551 4,797 5,772 6,068 6,396 8,658 9,102 9,594 11,544 12,136 12,792 13,653 17,316 18,204 19,188 19,721 27,306 34,632 36,408 38,376 39,442 54,612 59,163 78,884 109,224 118,326 157,768 177,489 236,652 354,978 473,304 709,956 and 1,419,912, with no remainder.
Since 1,419,912 cannot be divided by just 1 and 1,419,912, it is not a prime number.