Trisha Shetty (Editor)

221 (number)

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221
  
222 →

Factorization
  
13 × 17

Binary
  
110111012

Cardinal
  
two hundred twenty-one

Roman numeral
  
CCXXI

Ordinal
  
221st (two hundred and twenty-first)

221 (two hundred [and] twenty-one) is the natural number following 220 and preceding 222.

Contents

In mathematics

221 is:

  • a product of two prime numbers, 13 and 17, making it a semiprime
  • the sum of five consecutive prime numbers (37 + 41 + 43 + 47 + 53)
  • the sum of nine consecutive prime numbers (11 + 13 + 17 + 19 + 23 + 29 + 31 + 37 + 41)
  • a centered square number
  • Mertens function(221) = 5 a record high that stands until 554
  • If you deal 2 cards from a single deck of 52 cards, you have a 1 in 221 chance of getting 2 aces.

    • In other fields

    221 is:

  • SMTP status code for service closing transmission channel
  • 221B Baker Street, the fictional London residence of Sherlock Holmes
  • The experiment number for Sparky in the Disney franchise Lilo & Stitch.
  • .221 Remington Fireball, firearm cartridge

    • Historical years

    221 A.D. and 221 B.C.

    References

    221 (number) Wikipedia
    (Text) CC BY-SA