221 (number)
From Biocrawler, the free encyclopedia.
(Redirected from Two hundred twenty-one)
221 (two hundred [and] twenty-one) is the natural number following 220 and preceding 222.
| |
| Cardinal | Two hundred twenty-one |
| Ordinal | 221th |
| Factorization | 
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| Roman numeral | CCXXI |
| Binary | |
| Hexadecimal | |
| Hebrew | |
It is:
- sum of five consecutive primes (37 + 41 + 43 + 47 + 53)
- sum of nine consecutive primes (11 + 13 + 17 + 19 + 23 + 29 + 31 + 37 + 41)
- centered square number
- Mertens function(221) = 5 a record high that stands until 554
221 is also:
- SMTP status code for service closing transmission channel
- In the Sherlock Holmes mysteries by Arthur Conan Doyle, the house number of 221B Baker Street, where Sherlock Holmes and Dr. Watson lived at for many years with Mrs. Hudson as their landlady.
- The year AD 221 and 221 BC.
