def calcDivisor(factors):
  """
  Return the number from its prime factors.

  Args:
      factors: Dictionary of prime factors (keys) and their exponents (values).
  Returns:
      An integer. The number made of the prime factors.
  Usage:
      >>> calcDivisor({5: 3, 7: 2})
      6125
      >>> calcDivisor({2: 3, 5: 2, 7: 1})
      1400
  """

  acc = 1
  for f,e in factors.items():
    acc *= f**e
  return acc