A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1040760 can be evenly divided by 1 2 3 4 5 6 7 8 9 10 12 14 15 18 20 21 24 28 30 35 36 40 42 45 49 56 59 60 63 70 72 84 90 98 105 118 120 126 140 147 168 177 180 196 210 236 245 252 280 294 295 315 354 360 392 413 420 441 472 490 504 531 588 590 630 708 735 826 840 882 885 980 1,062 1,176 1,180 1,239 1,260 1,416 1,470 1,652 1,764 1,770 1,960 2,065 2,124 2,205 2,360 2,478 2,520 2,655 2,891 2,940 3,304 3,528 3,540 3,717 4,130 4,248 4,410 4,956 5,310 5,782 5,880 6,195 7,080 7,434 8,260 8,673 8,820 9,912 10,620 11,564 12,390 14,455 14,868 16,520 17,346 17,640 18,585 21,240 23,128 24,780 26,019 28,910 29,736 34,692 37,170 43,365 49,560 52,038 57,820 69,384 74,340 86,730 104,076 115,640 130,095 148,680 173,460 208,152 260,190 346,920 520,380 and 1,040,760, with no remainder.
Since 1,040,760 cannot be divided by just 1 and 1,040,760, it is not a prime number.