The Kapreakar Process
Find all 3digit primes which take just 6 steps in the Kaprekar Process (see below) to reach 495. The Kaprekar Process must always begin with a 3digit integer and will always terminate with the same number, 495. For example, take 323: 
1. 2. 3. 4. 5. 
Sort its digits into ascending order,
calling this A. So A = 233. Take the reverse of A and call it B, so
that
Subtract the smaller from the larger
number, giving B  A = 99. Call this 099 to preserve the 3digit format.B = 332. Repeat the process, giving 990  099 = 891. Keep on repeating, giving the series 323, 099, 891, 792, 693, 594, 495. 
As predicted, the series terminated with
495. It always does, regardless of which 3digit integer you start
with.
In this Puzzlet, you must
always start with a prime number. The challenge is to find those
3digit primes which complete the sequence in exactly 6 moves.

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Last Updated: January 12th, 2010.