| ||||
|---|---|---|---|---|
| Cardinal | two hundred twenty-seven | |||
| Ordinal | 227th (two hundred twenty-seventh) | |||
| Factorization | prime | |||
| Prime | yes | |||
| Greek numeral | ΣΚΖ´ | |||
| Roman numeral | CCXXVII | |||
| Binary | 111000112 | |||
| Ternary | 221023 | |||
| Senary | 10156 | |||
| Octal | 3438 | |||
| Duodecimal | 16B12 | |||
| Hexadecimal | E316 | |||
227 (two hundred [and] twenty-seven) is the natural number between 226 and 228. It is also a prime number.
In mathematics
227 is a twin prime and the start of a prime triplet (with 229 and 233). [1] It is a safe prime, as dividing it by two and rounding down produces the Sophie Germain prime 113. [2] It is also a regular prime, [3] a Pillai prime, [4] a Stern prime, [5] and a Ramanujan prime. [6]
227 and 229 form the first twin prime pair for which neither is a cluster prime.
The 227th harmonic number is the first to exceed six. [7] There are 227 different connected graphs with eight edges, [8] and 227 independent sets in a 3 × 4 grid graph. [9]
References
- ^ Sloane, N. J. A. (ed.). "Sequence A022004 (Initial members of prime triples (p, p+2, p+6))". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
- ^ Sloane, N. J. A. (ed.). "Sequence A005385 (Safe primes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
- ^ Sloane, N. J. A. (ed.). "Sequence A007703 (Regular primes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
- ^ Sloane, N. J. A. (ed.). "Sequence A063980 (Pillai primes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
- ^ Sloane, N. J. A. (ed.). "Sequence A042978 (Stern primes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
- ^ Sloane, N. J. A. (ed.). "Sequence A104272 (Ramanujan primes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
- ^ Sloane, N. J. A. (ed.). "Sequence A002387 (Least k such that H(k) > n, where H(k) is the harmonic number sum_{i=1..k} 1/i)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
- ^ Sloane, N. J. A. (ed.). "Sequence A002905 (Number of connected graphs with n edges)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
- ^ Sloane, N. J. A. (ed.). "Sequence A051736 (Number of 3 x n (0,1)-matrices with no consecutive 1's in any row or column)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
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