A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 2046240 can be evenly divided by 1 2 3 4 5 6 7 8 9 10 12 14 15 16 18 20 21 24 28 29 30 32 35 36 40 42 45 48 49 56 58 60 63 70 72 80 84 87 90 96 98 105 112 116 120 126 140 144 145 147 160 168 174 180 196 203 210 224 232 240 245 252 261 280 288 290 294 315 336 348 360 392 406 420 435 441 464 480 490 504 522 560 580 588 609 630 672 696 720 735 784 812 840 870 882 928 980 1,008 1,015 1,044 1,120 1,160 1,176 1,218 1,260 1,305 1,392 1,421 1,440 1,470 1,568 1,624 1,680 1,740 1,764 1,827 1,960 2,016 2,030 2,088 2,205 2,320 2,352 2,436 2,520 2,610 2,784 2,842 2,940 3,045 3,248 3,360 3,480 3,528 3,654 3,920 4,060 4,176 4,263 4,410 4,640 4,704 4,872 5,040 5,220 5,684 5,880 6,090 6,496 6,960 7,056 7,105 7,308 7,840 8,120 8,352 8,526 8,820 9,135 9,744 10,080 10,440 11,368 11,760 12,180 12,789 13,920 14,112 14,210 14,616 16,240 17,052 17,640 18,270 19,488 20,880 21,315 22,736 23,520 24,360 25,578 28,420 29,232 32,480 34,104 35,280 36,540 41,760 42,630 45,472 48,720 51,156 56,840 58,464 63,945 68,208 70,560 73,080 85,260 97,440 102,312 113,680 127,890 136,416 146,160 170,520 204,624 227,360 255,780 292,320 341,040 409,248 511,560 682,080 1,023,120 and 2,046,240, with no remainder.
Since 2,046,240 cannot be divided by just 1 and 2,046,240, it is not a prime number.