A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1384152 can be evenly divided by 1 2 3 4 6 7 8 11 12 14 21 22 24 28 33 42 44 49 56 66 77 84 88 98 107 132 147 154 168 196 214 231 264 294 308 321 392 428 462 539 588 616 642 749 856 924 1,078 1,176 1,177 1,284 1,498 1,617 1,848 2,156 2,247 2,354 2,568 2,996 3,234 3,531 4,312 4,494 4,708 5,243 5,992 6,468 7,062 8,239 8,988 9,416 10,486 12,936 14,124 15,729 16,478 17,976 20,972 24,717 28,248 31,458 32,956 41,944 49,434 57,673 62,916 65,912 98,868 115,346 125,832 173,019 197,736 230,692 346,038 461,384 692,076 and 1,384,152, with no remainder.
Since 1,384,152 cannot be divided by just 1 and 1,384,152, it is not a prime number.