well certain numbers work out better for systems. decimal seems the easiest, because most of us learned it first, but once you start working a bit in binary, it is the easiest-- especialy because you can quickly switch to octal or hexidecimal.
base 13 (13 remember is a prime number) doesn't have the same advantage.
we have vestiges of other numbering systems in our everyday life, (sixty minutes to an hour, sixty seconds to a minute, and 360 (six times sixty) degrees in a circle (based on 6 lovely equalateral trianges, each with 60 degree angles,nesting inside of a circle.
base twenty shows up in "score" and base 12, in shilling, and inches.
we have inherited all sorts of numbering systems, (and for the most part, don't even think twice about them.) but i can't think of any but binary that are based on prime numbers.
pentagon are used alegedly by witches, but not as a numbering system.
of course, you could use an base you wanted, and there might be unseen advantages, in going so.
