Why is Euler's totient function equal to (p-1)(q-1) when N=pq and p and q are prime?
45127
Why is Euler's totient function equal to $(p-1)(q-1)$ when $N=pq$ and $p$ and $q$ are prime in a clean intuitive way?
152299
Proving $a^{n-1} \equiv 1 \mod n $ when n is not prime.
78342
When is $\phi(n)$ a prime number?
32618
Suppose $p$ is a prime number such that $(p-1)/4$ and $(p+1)/2$ are also primes. Show that $p=13$
48587
Why is $1$ not a prime number?
15436
Find p and q s.t. $({p-1})^{q-1}+({q-1})^{p-1} \equiv 101 \pmod {pq}$
2218
Prove that $(n-1)! \equiv -1 \pmod{n}$ iff $n$ is prime [Wilson's Theorem]
66061
Why is the formula for calculating euler totient true?
83753
Why $\,p \cdot (p^{-1} \mod q) + q \cdot (q^{-1} \mod p) = pq + 1$?
95111
Elementary proof for $\sqrt{p_{n+1}} \notin \mathbb{Q}(\sqrt{p_1}, \sqrt{p_2}, \ldots, \sqrt{p_n})$ where $p_i$ are different prime numbers.
140830
Show $\,p\mid 9^q -1 \implies q\mid p-1$ for odd primes $p$ and $q$
5530
Intuitively, what separates Mersenne primes from Fermat primes?
147101
Show that if $p>5$ is prime, then $240 \mid (p^4-1)$
6700
An Olympiad problem in prime numbers :can we proof that "n" is prime in this case "
15915
For any prime $p > 3$, why is $p^2-1$ always divisible by 24?
44600
How can I prove: if $p $ is prime and $n>1$, then $ p^{\frac1n} $ is irrational?
20980
Prove that $\frac{p^p-1}{p-1}$ is not prime if $p \equiv 1 \pmod 4$