Number-theoretic Functions
General properties of number-theoretic function
number-theoretic function
Divisor function 1
Definition
number of divisors of 
Property
Divisor function 2
Definition
sum of the divisors of 
Property
If
, then 
is denominated as a perfect number.
is a perfect number when 
is prime, and every even perfect number can be expressed this way.Euler's function
Definition
a coset 
with quotient 
, designating the number of elements that are mutually prime with respect to 
.Properties
is prime 
Euler's theorem
Mobius function
Definition
when 
- If
is the product of 
different prime numbers, 
- If
contains a quadratic factor, 
Mobius' inversion formula
number-theoretic function
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