A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3167580 can be evenly divided by 1 2 3 4 5 6 10 12 13 15 20 26 30 31 39 52 60 62 65 78 93 124 130 131 155 156 186 195 260 262 310 372 390 393 403 465 524 620 655 780 786 806 930 1,209 1,310 1,572 1,612 1,703 1,860 1,965 2,015 2,418 2,620 3,406 3,930 4,030 4,061 4,836 5,109 6,045 6,812 7,860 8,060 8,122 8,515 10,218 12,090 12,183 16,244 17,030 20,305 20,436 24,180 24,366 25,545 34,060 40,610 48,732 51,090 52,793 60,915 81,220 102,180 105,586 121,830 158,379 211,172 243,660 263,965 316,758 527,930 633,516 791,895 1,055,860 1,583,790 and 3,167,580, with no remainder.
Since 3,167,580 cannot be divided by just 1 and 3,167,580, it is not a prime number.