A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1794528 can be evenly divided by 1 2 3 4 6 8 9 12 16 18 24 27 31 32 36 48 54 62 67 72 93 96 108 124 134 144 186 201 216 248 268 279 288 372 402 432 496 536 558 603 744 804 837 864 992 1,072 1,116 1,206 1,488 1,608 1,674 1,809 2,077 2,144 2,232 2,412 2,976 3,216 3,348 3,618 4,154 4,464 4,824 6,231 6,432 6,696 7,236 8,308 8,928 9,648 12,462 13,392 14,472 16,616 18,693 19,296 24,924 26,784 28,944 33,232 37,386 49,848 56,079 57,888 66,464 74,772 99,696 112,158 149,544 199,392 224,316 299,088 448,632 598,176 897,264 and 1,794,528, with no remainder.
Since 1,794,528 cannot be divided by just 1 and 1,794,528, it is not a prime number.