Base 64 to Base 25

Base 64

In base 64, each digit position represents a power of 64: the rightmost digit counts individual ones, the next counts groups of 64, the next counts groups of 64×64, and so on — the same place-value idea as base 10, just with 64 distinct digits instead of ten.

Base 25

Base 25 works the same way: the rightmost digit counts ones, the next counts groups of 25, the next counts groups of 25×25, and so on, using 25 distinct digits.