A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 953316 can be evenly divided by 1 2 3 4 6 7 9 12 13 14 18 21 26 27 28 36 39 42 52 54 63 78 84 91 97 108 117 126 156 182 189 194 234 252 273 291 351 364 378 388 468 546 582 679 702 756 819 873 1,092 1,164 1,261 1,358 1,404 1,638 1,746 2,037 2,457 2,522 2,619 2,716 3,276 3,492 3,783 4,074 4,914 5,044 5,238 6,111 7,566 8,148 8,827 9,828 10,476 11,349 12,222 15,132 17,654 18,333 22,698 24,444 26,481 34,047 35,308 36,666 45,396 52,962 68,094 73,332 79,443 105,924 136,188 158,886 238,329 317,772 476,658 and 953,316, with no remainder.
Since 953,316 cannot be divided by just 1 and 953,316, it is not a prime number.