A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3106350 can be evenly divided by 1 2 3 5 6 9 10 13 15 18 25 26 27 30 39 45 50 54 59 65 75 78 81 90 117 118 130 135 150 162 177 195 225 234 270 295 325 351 354 390 405 450 531 585 590 650 675 702 767 810 885 975 1,053 1,062 1,170 1,350 1,475 1,534 1,593 1,755 1,770 1,950 2,025 2,106 2,301 2,655 2,925 2,950 3,186 3,510 3,835 4,050 4,425 4,602 4,779 5,265 5,310 5,850 6,903 7,670 7,965 8,775 8,850 9,558 10,530 11,505 13,275 13,806 15,930 17,550 19,175 20,709 23,010 23,895 26,325 26,550 34,515 38,350 39,825 41,418 47,790 52,650 57,525 62,127 69,030 79,650 103,545 115,050 119,475 124,254 172,575 207,090 238,950 310,635 345,150 517,725 621,270 1,035,450 1,553,175 and 3,106,350, with no remainder.
Since 3,106,350 cannot be divided by just 1 and 3,106,350, it is not a prime number.