Efficient algorithm for conversion between numeral system

Question

Is there any efficient algorithm for conversion between numeral system when the size of source integer is arbitrary?

For example, assume that there is an integer arr

Answer 1

Divide by the base, push back the module, rinse and repeat while quotient != 0.

So, for example convert 148 in base 16

148 / 16 = 9 r 4
  9 / 16 = 0 r 9

So, 148 in hex is 0x94. This shouldn't take so long.