text: import math
  
  def prime_factors(n): 
      """ return a list prime factors for n """
      
      prime_factors = []
  
      while n % 2 == 0: 
          prime_factors.append(2)
          n = n / 2
      
      # int(math.sqrt(n))+1 is the max to test
      for i in range(3, int(math.sqrt(n))+1, 2):
          while n % i == 0: 
              prime_factors.append(i)
              n = n / i
  
      # Left over prime
      if n > 2: 
          prime_factors.append(n)
      
      return prime_factors
  
  print(prime_factors(600851475143))