A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1849320 can be evenly divided by 1 2 3 4 5 6 8 9 10 11 12 15 18 20 22 24 30 33 36 40 44 45 55 60 66 72 88 90 99 110 120 132 165 180 198 220 264 330 360 396 440 467 495 660 792 934 990 1,320 1,401 1,868 1,980 2,335 2,802 3,736 3,960 4,203 4,670 5,137 5,604 7,005 8,406 9,340 10,274 11,208 14,010 15,411 16,812 18,680 20,548 21,015 25,685 28,020 30,822 33,624 41,096 42,030 46,233 51,370 56,040 61,644 77,055 84,060 92,466 102,740 123,288 154,110 168,120 184,932 205,480 231,165 308,220 369,864 462,330 616,440 924,660 and 1,849,320, with no remainder.
Since 1,849,320 cannot be divided by just 1 and 1,849,320, it is not a prime number.