A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 2490670 can be evenly divided by 1 2 5 7 10 13 14 17 23 26 34 35 46 49 65 70 85 91 98 115 119 130 161 170 182 221 230 238 245 299 322 391 442 455 490 595 598 637 782 805 833 910 1,105 1,127 1,190 1,274 1,495 1,547 1,610 1,666 1,955 2,093 2,210 2,254 2,737 2,990 3,094 3,185 3,910 4,165 4,186 5,083 5,474 5,635 6,370 7,735 8,330 10,166 10,465 10,829 11,270 13,685 14,651 15,470 19,159 20,930 21,658 25,415 27,370 29,302 35,581 38,318 50,830 54,145 71,162 73,255 95,795 108,290 146,510 177,905 191,590 249,067 355,810 498,134 1,245,335 and 2,490,670, with no remainder.
Since 2,490,670 cannot be divided by just 1 and 2,490,670, it is not a prime number.