Английская Википедия:71 (number)
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Шаблон:Infobox number 71 (seventy-one) is the natural number following 70 and preceding 72.
In mathematics
Because both rearrangements of its digits (17 and 71) are prime numbers, 71 is an emirp and more generally a permutable prime.[1][2] It is the largest number which occurs as a prime factor of an order of a sporadic simple group, the largest (15th) supersingular prime.[3][4]
It is a Pillai prime, since <math>9!+1</math> is divisible by 71, but 71 is not one more than a multiple of 9.[5] It is part of the last known pair (71, 7) of Brown numbers, since <math>71^{2}=7!+1</math>.[6]
It is centered heptagonal number.[7]
See also
References
Шаблон:Reflist Шаблон:Integers
