Английская Википедия:271 (number)

Материал из Онлайн справочника
Перейти к навигацииПерейти к поиску

Шаблон:Infobox number 271 (two hundred [and] seventy-one) is the natural number after Шаблон:Num and before Шаблон:Num.

Properties

271 is a twin prime with 269,[1] a cuban prime (a prime number that is the difference of two consecutive cubes),[2] and a centered hexagonal number.[3] It is the smallest prime number bracketed on both sides by numbers divisible by cubes,[4] and the smallest prime number bracketed by numbers with five primes (counting repetitions) in their factorizations:[5]

<math>270=2\cdot 3^3\cdot 5</math> and <math>272=2^4\cdot 17</math>.

After 7, 271 is the second-smallest Eisenstein–Mersenne prime, one of the analogues of the Mersenne primes in the Eisenstein integers.[6]

271 is the largest prime factor of the five-digit repunit 11111,[7] and the largest prime number for which the decimal period of its multiplicative inverse is 5:[8]

<math>\frac{1}{271}=0.00369003690036900369\ldots</math>

It is a sexy prime with 277.

References

Шаблон:Reflist

Шаблон:Integers