A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 709632 can be evenly divided by 1 2 3 4 6 7 8 9 11 12 14 16 18 21 22 24 28 32 33 36 42 44 48 56 63 64 66 72 77 84 88 96 99 112 126 128 132 144 154 168 176 192 198 224 231 252 256 264 288 308 336 352 384 396 448 462 504 512 528 576 616 672 693 704 768 792 896 924 1,008 1,024 1,056 1,152 1,232 1,344 1,386 1,408 1,536 1,584 1,792 1,848 2,016 2,112 2,304 2,464 2,688 2,772 2,816 3,072 3,168 3,584 3,696 4,032 4,224 4,608 4,928 5,376 5,544 5,632 6,336 7,168 7,392 8,064 8,448 9,216 9,856 10,752 11,088 11,264 12,672 14,784 16,128 16,896 19,712 21,504 22,176 25,344 29,568 32,256 33,792 39,424 44,352 50,688 59,136 64,512 78,848 88,704 101,376 118,272 177,408 236,544 354,816 and 709,632, with no remainder.
Since 709,632 cannot be divided by just 1 and 709,632, it is not a prime number.