227 (number)

Short description: Natural number

| <- 226  | 227 |  228 ->

|
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← 220 221 222 223 224 225 226 227 228 229 →

List of numbers — Integers

← 0 100 200 300 400 500 600 700 800 900 →

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
Quaternary| 32034
Quinary| 14025
Senary| 10156
Octal| 3438
Duodecimal| 16B12
Hexadecimal| E316
Vigesimal| B720
Base 36| 6B36

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

1. ↑ Sloane, N. J. A., ed. "Sequence A022004 (Initial members of prime triples (p, p+2, p+6))". OEIS Foundation. https://oeis.org/A022004.
2. ↑ Sloane, N. J. A., ed. "Sequence A005385 (Safe primes)". OEIS Foundation. https://oeis.org/A005385.
3. ↑ Sloane, N. J. A., ed. "Sequence A007703 (Regular primes)". OEIS Foundation. https://oeis.org/A007703.
4. ↑ Sloane, N. J. A., ed. "Sequence A063980 (Pillai primes)". OEIS Foundation. https://oeis.org/A063980.
5. ↑ Sloane, N. J. A., ed. "Sequence A042978 (Stern primes)". OEIS Foundation. https://oeis.org/A042978.
6. ↑ Sloane, N. J. A., ed. "Sequence A104272 (Ramanujan primes)". OEIS Foundation. https://oeis.org/A104272.
7. ↑ 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)". OEIS Foundation. https://oeis.org/A002387.
8. ↑ Sloane, N. J. A., ed. "Sequence A002905 (Number of connected graphs with n edges)". OEIS Foundation. https://oeis.org/A002905.
9. ↑ 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)". OEIS Foundation. https://oeis.org/A051736.

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