221 (number)

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

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

Category:Integers