Number Theory Tutorials

Go through these tutorials, in order :

1. Hackerearth tutorial for primes, composites, sieve of erasthones, segmented sieve

2. Read upto "pre-computed primes method", from this article on factorisation

3. Number of divisors and Sum of divisors

note

Similarly, also remember the formula for product of divisors of a number $n$ :

$n^{\frac{d(n)}{2}}$

where $d(n)$ = number of divisors of $n$

4. Hackerearth tutorial on modular arithmetic, GCD, modular exponentiation and Fermat's Theorem

5. CP-algorithms Tutorial for Euler Totient Function (ETF), its properties and applications

6. Hackerearth tutorial for ETF

Additional Resources

• Revise Permutations and Combinations