Euler totient function

GPTKB entity

Statements (29)
Predicate Object
gptkbp:instanceOf arithmetical function
gptkbp:alsoKnownAs phi function
gptkbp:application gptkb:RSA_cryptosystem
gptkb:Euler's_theorem
primitive roots
gptkbp:codomain non-negative integers
gptkbp:defines number of positive integers up to n that are coprime to n
gptkbp:domain positive integers
gptkbp:field number theory
gptkbp:firstValues 1,1,2,2,4,2,6,4,6,4,10,4,12,6,8,8,16,6,18,8,12,10,22,8,20,12,18,12,28,8,30,16,20,16,24,12,36,18,24,16,40,12,42,20,24,22,46,16,42,20,32,24,52,18,40,24,36,28,58,16,60,30,36,32,48,20,66,32,44,24,70,24,72,36,40,36,60,24,78,32,54,40,82,24,64,42,56,40,88,24,72,44,60,46,72,32,96,42,60,40
gptkbp:form φ(n) = n * product over p|n of (1 - 1/p)
gptkbp:hasSpecialCase φ(1) = 1
φ(p) = p-1 for prime p
https://www.w3.org/2000/01/rdf-schema#label Euler totient function
gptkbp:introducedIn 18th century
gptkbp:multiplicative true
gptkbp:namedAfter gptkb:Leonhard_Euler
gptkbp:property even for n > 2
sum of φ(d) over all divisors d of n equals n
φ(mn) = φ(m)φ(n) if gcd(m,n)=1
φ(p^k) = p^k - p^{k-1} for prime p
gptkbp:relatedTo gptkb:Carmichael_function
gptkb:Möbius_function
gptkb:Dirichlet_convolution
Jordan's totient function
gptkbp:sequence gptkb:A000010_(OEIS)
gptkbp:symbol φ(n)
gptkbp:bfsParent gptkb:A000010_(OEIS)
gptkbp:bfsLayer 7