Given a character code as integer number in one encoding, how can you get the character code in, say, utf-8 and again as integer?
UTF-8 is a variable-length encoding, so I'll assume you really meant "Unicode code point". Use chr() to convert the character code to a character, decode it, and use ord() to get the code point.
chr()
ord()
>>> ord(chr(145).decode('koi8-r')) 9618