| ||||
|---|---|---|---|---|
| Cardinal | two hundred twenty-one | |||
| Ordinal | 221st (two hundred twenty-first) | |||
| Factorization | 13 × 17 | |||
| Greek numeral | ΣΚΑ´ | |||
| Roman numeral | CCXXI | |||
| Binary | 110111012 | |||
| Ternary | 220123 | |||
| Senary | 10056 | |||
| Octal | 3358 | |||
| Duodecimal | 16512 | |||
| Hexadecimal | DD16 | |||
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.[1]
221 is a centered square number.[2]
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.[3]
Sherlock Holmes's home address: 221B Baker Street.
References
- ↑ Sloane, N. J. A. (ed.). "Sequence A006094 (Products of 2 successive primes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
- ↑ Sloane, N. J. A. (ed.). "Sequence A001844 (Centered square numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
- ↑ Bollman, Mark (2014). "Example 2.4.12". Basic Gambling Mathematics: The Numbers Behind The Neon. CRC Press. p. 34. ISBN 9781482208948.
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