A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1071144 can be evenly divided by 1 2 3 4 6 8 9 12 18 19 24 27 29 36 38 54 57 58 72 76 81 87 108 114 116 152 162 171 174 216 228 232 243 261 324 342 348 456 486 513 522 551 648 684 696 783 972 1,026 1,044 1,102 1,368 1,539 1,566 1,653 1,944 2,052 2,088 2,204 2,349 3,078 3,132 3,306 4,104 4,408 4,617 4,698 4,959 6,156 6,264 6,612 7,047 9,234 9,396 9,918 12,312 13,224 14,094 14,877 18,468 18,792 19,836 28,188 29,754 36,936 39,672 44,631 56,376 59,508 89,262 119,016 133,893 178,524 267,786 357,048 535,572 and 1,071,144, with no remainder.
Since 1,071,144 cannot be divided by just 1 and 1,071,144, it is not a prime number.