Euler function
Euler function, symbolically written as [Phi] ( n- ) [Phi] (n-), which is smaller than the n- n-and the n- n-number of prime numbers
nature
①
For the prime number n- n-
z ( n ) = n - 1 z (n) = n-1
②
For n- = P K n-PK =
z ( n ) = ( p - 1 ) * p k - 1 z (n) = (p-1 ) * pk-1
③
Multiplicative function []
for G C D ( n- , m ) = . 1 GCD (n-, m) =. 1
z ( n * m ) = z ( n ) * f ( m ) f (n * m) = z (n) * f (m)
④
[Formula] is calculated
for the n- = [pi P K I I n-= Πpiki
z ( n ) = n * W ( 1 - 1 p i ) z (n) = n * P (1-1pi)
⑤
Euler's theorem []
for coprime A , m A, m
aφ(m)≡1(modm)aφ(m)≡1(modm)
⑥
Less than n- n-and the n- n-prime number and:
S=n∗φ(n)2S=n∗φ(n)2
⑦
For the prime number P P
when the n- MOD P = 0 nmodp = 0
z ( n * p ) = z ( n ) * p z (n * p) = z (n) * p
If the n- MOD P ≠ 0 nmodp ≠ 0
z ( n * p ) = z ( n ) * ( p - 1 ) z (n * p) = z (n) * (p-1 )
⑧
∑d|nφ(d)=n∑d|nφ(d)=n
φ ( n ) = Σ d | n μ ( d ) * n d