A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 496944 can be evenly divided by 1 2 3 4 6 7 8 9 12 14 16 17 18 21 24 28 29 34 36 42 48 51 56 58 63 68 72 84 87 102 112 116 119 126 136 144 153 168 174 203 204 232 238 252 261 272 306 336 348 357 406 408 464 476 493 504 522 609 612 696 714 812 816 952 986 1,008 1,044 1,071 1,218 1,224 1,392 1,428 1,479 1,624 1,827 1,904 1,972 2,088 2,142 2,436 2,448 2,856 2,958 3,248 3,451 3,654 3,944 4,176 4,284 4,437 4,872 5,712 5,916 6,902 7,308 7,888 8,568 8,874 9,744 10,353 11,832 13,804 14,616 17,136 17,748 20,706 23,664 27,608 29,232 31,059 35,496 41,412 55,216 62,118 70,992 82,824 124,236 165,648 248,472 and 496,944, with no remainder.
Since 496,944 cannot be divided by just 1 and 496,944, it is not a prime number.