We have a number expressed in a base of 9, instead of the most common decimal base.
Then, is we have the number 82104 in 9-base, it means that we can expand it as:

We then can expand this as:

We can finally calculate what this number is in decimal form by finishing simplyfing the expression above:

Answer:
If we decompose this number given the base 9, we get the following terms:

The decimal form of 82104(nine) is 54031.