A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 2571030 can be evenly divided by 1 2 3 5 6 7 9 10 11 14 15 18 21 22 30 33 35 42 45 49 53 55 63 66 70 77 90 98 99 105 106 110 126 147 154 159 165 198 210 231 245 265 294 315 318 330 371 385 441 462 477 490 495 530 539 583 630 693 735 742 770 795 882 954 990 1,078 1,113 1,155 1,166 1,386 1,470 1,590 1,617 1,749 1,855 2,205 2,226 2,310 2,385 2,597 2,695 2,915 3,234 3,339 3,465 3,498 3,710 4,081 4,410 4,770 4,851 5,194 5,247 5,390 5,565 5,830 6,678 6,930 7,791 8,085 8,162 8,745 9,702 10,494 11,130 12,243 12,985 15,582 16,170 16,695 17,490 20,405 23,373 24,255 24,486 25,970 26,235 28,567 33,390 36,729 38,955 40,810 46,746 48,510 52,470 57,134 61,215 73,458 77,910 85,701 116,865 122,430 142,835 171,402 183,645 233,730 257,103 285,670 367,290 428,505 514,206 857,010 1,285,515 and 2,571,030, with no remainder.
Since 2,571,030 cannot be divided by just 1 and 2,571,030, it is not a prime number.