A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1734432 can be evenly divided by 1 2 3 4 6 7 8 12 14 16 21 24 28 29 32 42 48 56 58 84 87 89 96 112 116 168 174 178 203 224 232 267 336 348 356 406 464 534 609 623 672 696 712 812 928 1,068 1,218 1,246 1,392 1,424 1,624 1,869 2,136 2,436 2,492 2,581 2,784 2,848 3,248 3,738 4,272 4,872 4,984 5,162 6,496 7,476 7,743 8,544 9,744 9,968 10,324 14,952 15,486 18,067 19,488 19,936 20,648 29,904 30,972 36,134 41,296 54,201 59,808 61,944 72,268 82,592 108,402 123,888 144,536 216,804 247,776 289,072 433,608 578,144 867,216 and 1,734,432, with no remainder.
Since 1,734,432 cannot be divided by just 1 and 1,734,432, it is not a prime number.