A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 5028426 can be evenly divided by 1 2 3 6 9 13 18 19 26 27 29 38 39 54 57 58 78 87 114 117 169 171 174 234 247 261 338 342 351 377 494 507 513 522 551 702 741 754 783 1,014 1,026 1,102 1,131 1,482 1,521 1,566 1,653 2,223 2,262 3,042 3,211 3,306 3,393 4,446 4,563 4,901 4,959 6,422 6,669 6,786 7,163 9,126 9,633 9,802 9,918 10,179 13,338 14,326 14,703 14,877 19,266 20,358 21,489 28,899 29,406 29,754 42,978 44,109 57,798 64,467 86,697 88,218 93,119 128,934 132,327 173,394 186,238 193,401 264,654 279,357 386,802 558,714 838,071 1,676,142 2,514,213 and 5,028,426, with no remainder.
Since 5,028,426 cannot be divided by just 1 and 5,028,426, it is not a prime number.