186 (one hundred
ndeighty-six) is the
natural number
In mathematics, the natural numbers are the numbers 0, 1, 2, 3, and so on, possibly excluding 0. Some start counting with 0, defining the natural numbers as the non-negative integers , while others start with 1, defining them as the positive in ...
following
185 and preceding
187.
In mathematics
There is no integer with exactly 186
coprime
In number theory, two integers and are coprime, relatively prime or mutually prime if the only positive integer that is a divisor of both of them is 1. Consequently, any prime number that divides does not divide , and vice versa. This is equiv ...
s less than it, so 186 is a
nontotient
In number theory, a nontotient is a positive integer ''n'' which is not a totient number: it is not in the range of Euler's totient function φ, that is, the equation φ(''x'') = ''n'' has no solution ''x''. In other words, ''n'' is a nontotie ...
. It is also never the difference between an integer and the total of coprimes below it, so it is a
noncototient
In number theory, a noncototient is a positive integer that cannot be expressed as the difference between a positive integer and the number of coprime integers below it. That is, , where stands for Euler's totient function
In number theory ...
.
There are 186 different
pentahexes, shapes formed by gluing together five regular hexagons, when rotations of shapes are counted as distinct from each other.
186 is a Fine number.
See also
*
References
Integers
{{Num-stub