Sum of divisors and Euler phi function of a number
115258
Find all positive integers $n$ such that $\phi(n)+\sigma(n)=2n$.
102086
Prove a property of divisor function
121661
Evaluating the sum $\Sigma \, \frac{1}{k(k+p)}$
105623
Prime factorization knowing n and Euler's function
78342
When is $\phi(n)$ a prime number?
137175
Fermat's little theorem proof by Euler
125188
how to prove $m^{\phi(n)}+n^{\phi(m)}\equiv 1 \pmod{mn}$ where m and n are relatively prime?
121554
Finding $\sum\frac{1}{2^n(n+1)}$
86051
Find the sum of reciprocals of divisors given the sum of divisors
880
Find all n such that $\phi(n) = n/2$
44575
The sigma function (sum of divisors) multiplicative proof
80670
'Lines' in the Euler phi graph
84879
Solving infinite sums with primes.
41141
Proving that $\frac{\phi^{400}+1}{\phi^{200}}$ is an integer.
58480
Computing sums of divisors in $O(\sqrt n)$ time?
81723
Infinitely many primes proof using Euler's totient
135302
Proof on Euler totient function