There are 362,880 different numbers that use the digits 1 to 9 exactly once (like 187,432,569).

Of these, what percentage are prime numbers?

0%. any number whose digits' sum is a multiple of three is divisible by three, making it not prime. 1+2+3+4+5+6+7+8+9=45, a multiple of three.

Posted by ethan on 2003-05-08 10:51:19