A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 2498490 can be evenly divided by 1 2 3 5 6 9 10 15 17 18 23 30 34 45 46 51 69 71 85 90 102 115 138 142 153 170 207 213 230 255 306 345 355 391 414 426 510 639 690 710 765 782 1,035 1,065 1,173 1,207 1,278 1,530 1,633 1,955 2,070 2,130 2,346 2,414 3,195 3,266 3,519 3,621 3,910 4,899 5,865 6,035 6,390 7,038 7,242 8,165 9,798 10,863 11,730 12,070 14,697 16,330 17,595 18,105 21,726 24,495 27,761 29,394 35,190 36,210 48,990 54,315 55,522 73,485 83,283 108,630 138,805 146,970 166,566 249,849 277,610 416,415 499,698 832,830 1,249,245 and 2,498,490, with no remainder.
Since 2,498,490 cannot be divided by just 1 and 2,498,490, it is not a prime number.