def prime_factors(n):
	""" Return the prime factors of the given number. """
	# < 1 is a special case
	if n <= 1:
		return [1]
	factors = []
	lastresult = n
	while True:
		if lastresult == 1:
			break
		c = 2
		while True:
			if lastresult % c == 0:
				break
			c += 1
		factors.append(c)
		lastresult /= c
	return factors