For this and also problem 33 I found it very useful to implement a function which returns an integer that is invariant to permuting the digits in .

This can be done by returning a product of prime factors where the exponents are the number of times each digit occur in n.

In python this can be implemented as follows:

pfs = (2, 3, 5, 7, 11, 13, 17, 19, 23, 29)

def p(n, ten_pfs=pfs):
    result = 1
    while n:
        n, d = divmod(n, 10)
        result *= pfs[d]
    return result

So for the example given . Then it is just a matter of finding those where by iterating over the possible values of .