title: 221 (number)
text: # 221 (number)
  
  221 (two hundred [and] twenty-one) is the natural number following 220 and preceding 222.
  
  ## In mathematics
  
  Its factorization as 13 × 17 makes 221 the product of two consecutive prime numbers, the sixth smallest such product.
  
  221 is a centered square number.
  
  ## In other fields
  
  In Texas hold 'em, the probability of being dealt pocket aces (the strongest possible outcome in the initial deal of two cards per player) is 1/221.
  
  Sherlock Holmes's home address: 221B Baker Street.
  
  