A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 2351250 can be evenly divided by 1 2 3 5 6 9 10 11 15 18 19 22 25 30 33 38 45 50 55 57 66 75 90 95 99 110 114 125 150 165 171 190 198 209 225 250 275 285 330 342 375 418 450 475 495 550 570 625 627 750 825 855 950 990 1,045 1,125 1,250 1,254 1,375 1,425 1,650 1,710 1,875 1,881 2,090 2,250 2,375 2,475 2,750 2,850 3,135 3,750 3,762 4,125 4,275 4,750 4,950 5,225 5,625 6,270 6,875 7,125 8,250 8,550 9,405 10,450 11,250 11,875 12,375 13,750 14,250 15,675 18,810 20,625 21,375 23,750 24,750 26,125 31,350 35,625 41,250 42,750 47,025 52,250 61,875 71,250 78,375 94,050 106,875 123,750 130,625 156,750 213,750 235,125 261,250 391,875 470,250 783,750 1,175,625 and 2,351,250, with no remainder.
Since 2,351,250 cannot be divided by just 1 and 2,351,250, it is not a prime number.