A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 2117500 can be evenly divided by 1 2 4 5 7 10 11 14 20 22 25 28 35 44 50 55 70 77 100 110 121 125 140 154 175 220 242 250 275 308 350 385 484 500 550 605 625 700 770 847 875 1,100 1,210 1,250 1,375 1,540 1,694 1,750 1,925 2,420 2,500 2,750 3,025 3,388 3,500 3,850 4,235 4,375 5,500 6,050 6,875 7,700 8,470 8,750 9,625 12,100 13,750 15,125 16,940 17,500 19,250 21,175 27,500 30,250 38,500 42,350 48,125 60,500 75,625 84,700 96,250 105,875 151,250 192,500 211,750 302,500 423,500 529,375 1,058,750 and 2,117,500, with no remainder.
Since 2,117,500 cannot be divided by just 1 and 2,117,500, it is not a prime number.