A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1814274 can be evenly divided by 1 2 3 6 7 9 11 14 17 18 21 22 33 34 42 49 51 63 66 77 98 99 102 119 121 126 147 153 154 187 198 231 238 242 294 306 357 363 374 441 462 539 561 693 714 726 833 847 882 1,071 1,078 1,089 1,122 1,309 1,386 1,617 1,666 1,683 1,694 2,057 2,142 2,178 2,499 2,541 2,618 3,234 3,366 3,927 4,114 4,851 4,998 5,082 5,929 6,171 7,497 7,623 7,854 9,163 9,702 11,781 11,858 12,342 14,399 14,994 15,246 17,787 18,326 18,513 23,562 27,489 28,798 35,574 37,026 43,197 53,361 54,978 82,467 86,394 100,793 106,722 129,591 164,934 201,586 259,182 302,379 604,758 907,137 and 1,814,274, with no remainder.
Since 1,814,274 cannot be divided by just 1 and 1,814,274, it is not a prime number.