def truncatable_prime(num):
digit = solutions.get_digits(num)
divisor = 1
while num / divisor:
val = num / divisor
if not solutions.is_prime(val) or val == 1:
return False
val = num % divisor
if val == 1:
return False
elif val > 0 and not solutions.is_prime(val):
return False
divisor *= 10
return True
def num_to_words(num, items=None):
items = items or []
if num in num_to_word:
items.append(num)
return items
digit = solutions.get_digits(num)
nth = 10 ** (digit - 1)
div = num / nth
rem = num % nth
if div * nth in num_to_word:
items.append(div * nth)
else:
items.append((div, nth))
if rem in num_to_word:
items.append(rem)
elif rem >= 1:
num_to_words(rem, items)
return items
