Euler totient function φ(n)

GPTKB entity

Statements (32)
Predicate Object
gptkbp:instanceOf arithmetic function
gptkbp:alsoKnownAs gptkb:Euler's_totient_function
phi function
gptkbp:application gptkb:RSA_cryptosystem
gptkb:Euler's_theorem
number theory
gptkbp:codomain non-negative integers
gptkbp:defines number of positive integers less than or equal to n that are coprime to n
gptkbp:designer no simple closed form
gptkbp:domain positive integers
gptkbp:form φ(n) = n × Π(1 - 1/p) over all distinct prime divisors p of n
gptkbp:hasSpecialCase φ(1) = 1
φ(p) = p-1 for prime p
https://www.w3.org/2000/01/rdf-schema#label Euler totient function φ(n)
gptkbp:introduced gptkb:Leonhard_Euler
gptkbp:introducedIn 1763
gptkbp:namedAfter gptkb:Leonhard_Euler
gptkbp:notation φ(n)
phi(n)
gptkbp:property sum of φ(d) over all divisors d of n equals n
φ(mn) = φ(m)φ(n) if gcd(m, n) = 1
multiplicative function
average order is 6n/π²
gptkbp:relatedTo gptkb:Carmichael_function
gptkb:Möbius_function
prime numbers
gptkbp:sequence gptkb:A000010_(OEIS)
gptkbp:usedIn cryptography
group theory
modular arithmetic
gptkbp:bfsParent gptkb:A002322
gptkbp:bfsLayer 8