Tagged Questions
10
votes
4answers
768 views
Highest power of a prime $p$ dividing $N!$
How does one find the highest power of a prime $p$ that divides $N!$ and other related products?
Related question: How many zeros are there at the end of $N!$?
This is being done to reduce ...
6
votes
4answers
455 views
How do I compute $a^b\,\bmod c$ by hand?
How do I efficiently compute $a^b\,\bmod c$:
When $b$ is huge, for instance $5^{844325}\,\bmod 21$?
When $b$ is less than $c$ but it would still be a lot of work to multiply $a$ by itself $b$ times, ...
