In Direct mapped cache:
Address format= Tag + cache index + Offset
Offset = log(block size) = log(32B) = log(2^5) =5 bits
index = log(cache size / block size) = log(32KB)/log(32B) = 10 bits
Finally Tag = Total bits - index - offset = 32 - 10 - 5 = 17 bits
NOTE: Base of log is 2