A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 167580 can be evenly divided by 1 2 3 4 5 6 7 9 10 12 14 15 18 19 20 21 28 30 35 36 38 42 45 49 57 60 63 70 76 84 90 95 98 105 114 126 133 140 147 171 180 190 196 210 228 245 252 266 285 294 315 342 380 399 420 441 490 532 570 588 630 665 684 735 798 855 882 931 980 1,140 1,197 1,260 1,330 1,470 1,596 1,710 1,764 1,862 1,995 2,205 2,394 2,660 2,793 2,940 3,420 3,724 3,990 4,410 4,655 4,788 5,586 5,985 7,980 8,379 8,820 9,310 11,172 11,970 13,965 16,758 18,620 23,940 27,930 33,516 41,895 55,860 83,790 and 167,580, with no remainder.
Since 167,580 cannot be divided by just 1 and 167,580, it is not a prime number.