A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1502064 can be evenly divided by 1 2 3 4 6 8 9 12 16 18 19 24 27 36 38 48 54 57 61 72 76 81 108 114 122 144 152 162 171 183 216 228 244 304 324 342 366 432 456 488 513 549 648 684 732 912 976 1,026 1,098 1,159 1,296 1,368 1,464 1,539 1,647 2,052 2,196 2,318 2,736 2,928 3,078 3,294 3,477 4,104 4,392 4,636 4,941 6,156 6,588 6,954 8,208 8,784 9,272 9,882 10,431 12,312 13,176 13,908 18,544 19,764 20,862 24,624 26,352 27,816 31,293 39,528 41,724 55,632 62,586 79,056 83,448 93,879 125,172 166,896 187,758 250,344 375,516 500,688 751,032 and 1,502,064, with no remainder.
Since 1,502,064 cannot be divided by just 1 and 1,502,064, it is not a prime number.