A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3927528 can be evenly divided by 1 2 3 4 6 8 9 11 12 18 19 22 24 27 29 33 36 38 44 54 57 58 66 72 76 81 87 88 99 108 114 116 132 152 162 171 174 198 209 216 228 232 261 264 297 319 324 342 348 396 418 456 513 522 551 594 627 638 648 684 696 783 792 836 891 957 1,026 1,044 1,102 1,188 1,254 1,276 1,368 1,539 1,566 1,653 1,672 1,782 1,881 1,914 2,052 2,088 2,204 2,349 2,376 2,508 2,552 2,871 3,078 3,132 3,306 3,564 3,762 3,828 4,104 4,408 4,698 4,959 5,016 5,643 5,742 6,061 6,156 6,264 6,612 7,128 7,524 7,656 8,613 9,396 9,918 11,286 11,484 12,122 12,312 13,224 14,877 15,048 16,929 17,226 18,183 18,792 19,836 22,572 22,968 24,244 25,839 29,754 33,858 34,452 36,366 39,672 44,631 45,144 48,488 51,678 54,549 59,508 67,716 68,904 72,732 89,262 103,356 109,098 119,016 135,432 145,464 163,647 178,524 206,712 218,196 327,294 357,048 436,392 490,941 654,588 981,882 1,309,176 1,963,764 and 3,927,528, with no remainder.
Since 3,927,528 cannot be divided by just 1 and 3,927,528, it is not a prime number.