A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1152060 can be evenly divided by 1 2 3 4 5 6 7 10 12 13 14 15 20 21 26 28 30 35 39 42 52 60 65 70 78 84 91 105 130 140 156 182 195 210 211 260 273 364 390 420 422 455 546 633 780 844 910 1,055 1,092 1,266 1,365 1,477 1,820 2,110 2,532 2,730 2,743 2,954 3,165 4,220 4,431 5,460 5,486 5,908 6,330 7,385 8,229 8,862 10,972 12,660 13,715 14,770 16,458 17,724 19,201 22,155 27,430 29,540 32,916 38,402 41,145 44,310 54,860 57,603 76,804 82,290 88,620 96,005 115,206 164,580 192,010 230,412 288,015 384,020 576,030 and 1,152,060, with no remainder.
Since 1,152,060 cannot be divided by just 1 and 1,152,060, it is not a prime number.