A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 9521712 can be evenly divided by 1 2 3 4 6 8 9 12 16 18 24 27 31 36 48 54 62 72 79 81 93 108 124 144 158 162 186 216 237 243 248 279 316 324 372 432 474 486 496 558 632 648 711 744 837 948 972 1,116 1,264 1,296 1,422 1,488 1,674 1,896 1,944 2,133 2,232 2,449 2,511 2,844 3,348 3,792 3,888 4,266 4,464 4,898 5,022 5,688 6,399 6,696 7,347 7,533 8,532 9,796 10,044 11,376 12,798 13,392 14,694 15,066 17,064 19,197 19,592 20,088 22,041 25,596 29,388 30,132 34,128 38,394 39,184 40,176 44,082 51,192 58,776 60,264 66,123 76,788 88,164 102,384 117,552 120,528 132,246 153,576 176,328 198,369 264,492 307,152 352,656 396,738 528,984 595,107 793,476 1,057,968 1,190,214 1,586,952 2,380,428 3,173,904 4,760,856 and 9,521,712, with no remainder.
Since 9,521,712 cannot be divided by just 1 and 9,521,712, it is not a prime number.