A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 836550 can be evenly divided by 1 2 3 5 6 9 10 11 13 15 18 22 25 26 30 33 39 45 50 55 65 66 75 78 90 99 110 117 130 143 150 165 169 195 198 225 234 275 286 325 330 338 390 429 450 495 507 550 585 650 715 825 845 858 975 990 1,014 1,170 1,287 1,430 1,521 1,650 1,690 1,859 1,950 2,145 2,475 2,535 2,574 2,925 3,042 3,575 3,718 4,225 4,290 4,950 5,070 5,577 5,850 6,435 7,150 7,605 8,450 9,295 10,725 11,154 12,675 12,870 15,210 16,731 18,590 21,450 25,350 27,885 32,175 33,462 38,025 46,475 55,770 64,350 76,050 83,655 92,950 139,425 167,310 278,850 418,275 and 836,550, with no remainder.
Since 836,550 cannot be divided by just 1 and 836,550, it is not a prime number.