A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3101028 can be evenly divided by 1 2 3 4 6 7 12 14 19 21 28 29 38 42 57 58 67 76 84 87 114 116 133 134 174 201 203 228 266 268 348 399 402 406 469 532 551 609 798 804 812 938 1,102 1,218 1,273 1,407 1,596 1,653 1,876 1,943 2,204 2,436 2,546 2,814 3,306 3,819 3,857 3,886 5,092 5,628 5,829 6,612 7,638 7,714 7,772 8,911 11,571 11,658 13,601 15,276 15,428 17,822 23,142 23,316 26,733 27,202 35,644 36,917 40,803 46,284 53,466 54,404 73,834 81,606 106,932 110,751 147,668 163,212 221,502 258,419 443,004 516,838 775,257 1,033,676 1,550,514 and 3,101,028, with no remainder.
Since 3,101,028 cannot be divided by just 1 and 3,101,028, it is not a prime number.