A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 857010 can be evenly divided by 1 2 3 5 6 7 10 11 14 15 21 22 30 33 35 42 49 53 55 66 70 77 98 105 106 110 147 154 159 165 210 231 245 265 294 318 330 371 385 462 490 530 539 583 735 742 770 795 1,078 1,113 1,155 1,166 1,470 1,590 1,617 1,749 1,855 2,226 2,310 2,597 2,695 2,915 3,234 3,498 3,710 4,081 5,194 5,390 5,565 5,830 7,791 8,085 8,162 8,745 11,130 12,243 12,985 15,582 16,170 17,490 20,405 24,486 25,970 28,567 38,955 40,810 57,134 61,215 77,910 85,701 122,430 142,835 171,402 285,670 428,505 and 857,010, with no remainder.
Since 857,010 cannot be divided by just 1 and 857,010, it is not a prime number.