A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 2486250 can be evenly divided by 1 2 3 5 6 9 10 13 15 17 18 25 26 30 34 39 45 50 51 65 75 78 85 90 102 117 125 130 150 153 170 195 221 225 234 250 255 306 325 375 390 425 442 450 510 585 625 650 663 750 765 850 975 1,105 1,125 1,170 1,250 1,275 1,326 1,530 1,625 1,875 1,950 1,989 2,125 2,210 2,250 2,550 2,925 3,250 3,315 3,750 3,825 3,978 4,250 4,875 5,525 5,625 5,850 6,375 6,630 7,650 8,125 9,750 9,945 10,625 11,050 11,250 12,750 14,625 16,250 16,575 19,125 19,890 21,250 24,375 27,625 29,250 31,875 33,150 38,250 48,750 49,725 55,250 63,750 73,125 82,875 95,625 99,450 138,125 146,250 165,750 191,250 248,625 276,250 414,375 497,250 828,750 1,243,125 and 2,486,250, with no remainder.
Since 2,486,250 cannot be divided by just 1 and 2,486,250, it is not a prime number.