jizoku.py

#!/usr/bin/env python

def jizoku(i):
	if i < 10:
		return 0
	a = 1
	while i > 0:
		a *= i % 10
		i /= 10
	return jizoku(a) + 1

def jizoku_of(n):
	i = 0
	while True:
		if jizoku(i) == n:
			return i
		i += 1

print jizoku_of(5)