A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 2810610 can be evenly divided by 1 2 3 5 6 9 10 11 15 17 18 22 30 33 34 45 51 55 66 85 90 99 102 110 153 165 167 170 187 198 255 306 330 334 374 495 501 510 561 765 835 935 990 1,002 1,122 1,503 1,530 1,670 1,683 1,837 1,870 2,505 2,805 2,839 3,006 3,366 3,674 5,010 5,511 5,610 5,678 7,515 8,415 8,517 9,185 11,022 14,195 15,030 16,533 16,830 17,034 18,370 25,551 27,555 28,390 31,229 33,066 42,585 51,102 55,110 62,458 82,665 85,170 93,687 127,755 156,145 165,330 187,374 255,510 281,061 312,290 468,435 562,122 936,870 1,405,305 and 2,810,610, with no remainder.
Since 2,810,610 cannot be divided by just 1 and 2,810,610, it is not a prime number.