A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 931260 can be evenly divided by 1 2 3 4 5 6 10 11 12 15 17 20 22 30 33 34 44 51 55 60 66 68 83 85 102 110 132 165 166 170 187 204 220 249 255 330 332 340 374 415 498 510 561 660 748 830 913 935 996 1,020 1,122 1,245 1,411 1,660 1,826 1,870 2,244 2,490 2,739 2,805 2,822 3,652 3,740 4,233 4,565 4,980 5,478 5,610 5,644 7,055 8,466 9,130 10,956 11,220 13,695 14,110 15,521 16,932 18,260 21,165 27,390 28,220 31,042 42,330 46,563 54,780 62,084 77,605 84,660 93,126 155,210 186,252 232,815 310,420 465,630 and 931,260, with no remainder.
Since 931,260 cannot be divided by just 1 and 931,260, it is not a prime number.