A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 274176 can be evenly divided by 1 2 3 4 6 7 8 9 12 14 16 17 18 21 24 28 32 34 36 42 48 51 56 63 64 68 72 84 96 102 112 119 126 128 136 144 153 168 192 204 224 238 252 256 272 288 306 336 357 384 408 448 476 504 544 576 612 672 714 768 816 896 952 1,008 1,071 1,088 1,152 1,224 1,344 1,428 1,632 1,792 1,904 2,016 2,142 2,176 2,304 2,448 2,688 2,856 3,264 3,808 4,032 4,284 4,352 4,896 5,376 5,712 6,528 7,616 8,064 8,568 9,792 11,424 13,056 15,232 16,128 17,136 19,584 22,848 30,464 34,272 39,168 45,696 68,544 91,392 137,088 and 274,176, with no remainder.
Since 274,176 cannot be divided by just 1 and 274,176, it is not a prime number.