A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1161270 can be evenly divided by 1 2 3 5 6 9 10 11 15 17 18 22 23 27 30 33 34 45 46 51 54 55 66 69 85 90 99 102 110 115 135 138 153 165 170 187 198 207 230 253 255 270 297 306 330 345 374 391 414 459 495 506 510 561 594 621 690 759 765 782 918 935 990 1,035 1,122 1,173 1,242 1,265 1,485 1,518 1,530 1,683 1,870 1,955 2,070 2,277 2,295 2,346 2,530 2,805 2,970 3,105 3,366 3,519 3,795 3,910 4,301 4,554 4,590 5,049 5,610 5,865 6,210 6,831 7,038 7,590 8,415 8,602 10,098 10,557 11,385 11,730 12,903 13,662 16,830 17,595 21,114 21,505 22,770 25,245 25,806 34,155 35,190 38,709 43,010 50,490 52,785 64,515 68,310 77,418 105,570 116,127 129,030 193,545 232,254 387,090 580,635 and 1,161,270, with no remainder.
Since 1,161,270 cannot be divided by just 1 and 1,161,270, it is not a prime number.