A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1165710 can be evenly divided by 1 2 3 5 6 7 10 13 14 15 21 26 30 35 39 42 49 61 65 70 78 91 98 105 122 130 147 182 183 195 210 245 273 294 305 366 390 427 455 490 546 610 637 735 793 854 910 915 1,274 1,281 1,365 1,470 1,586 1,830 1,911 2,135 2,379 2,562 2,730 2,989 3,185 3,822 3,965 4,270 4,758 5,551 5,978 6,370 6,405 7,930 8,967 9,555 11,102 11,895 12,810 14,945 16,653 17,934 19,110 23,790 27,755 29,890 33,306 38,857 44,835 55,510 77,714 83,265 89,670 116,571 166,530 194,285 233,142 388,570 582,855 and 1,165,710, with no remainder.
Since 1,165,710 cannot be divided by just 1 and 1,165,710, it is not a prime number.