Find all positive integers $n$ such that $\phi(n)=10$
43865
Find all positive integers $n$ such that $\phi(n)=6$.
157711
Number Theory: Prove that $m | \phi(a^m - 1)$
142931
Problem on Euler's Phi function
16235
Prove by induction that every positive integer is represented by some binary number?
84930
How to justify $\phi(n) \ge \sqrt{n}$
97196
$k^{\phi(l)} + l^{\phi(k)} \equiv1\pmod{lk}\,$ if $\,\gcd(l,k)=1$
116540
Positive integers less than 1000 without repeated digits
149509
What method would you go through to find an $n$ such that $\phi(n)=100$?
106030
Find all the positive integer
22367
How do I prove that for every positive integer $n$, there exist $n$ consecutive positive integers, each of which is composite?
53670
Prove that it is possible to choose $100$ out of the first $200$ positive integers
27069
sum of all positive integers less than $n$ and relatively prime to $n$
123891
There are finitely many maps on nonnegative integers satisfying $\phi(ab)=\phi(a)+\phi(b)$
91889
Prove $\phi^n = \phi F_n + \text{(another Fibonacci number)}$ using mathematical induction.
56574
For any integer $a,b$ let $N_{a,b}$ denote the number of positive integer $x<1000$ satisfying $x= a( mod\;27)$ and $x=b(mod\;37)$. Then
139383
Prove that $\tau(2^n-1) \geq \tau(n)$ for all positive integers $n$.
87843
Combinatorial proof that $\frac{({10!})!}{{10!}^{9!}}$ is an integer