Tau and Prime

A natural number $n>1$ is called as special , if $n=p^{|p-q|}q^{p+q}$ with $p$ and $q$ different primes. Define $h(n)$ for $n>1$ natural as product of prime numbers that less than or equal to $n$ . If $\tau(n)$ is the number of positive divisors of $n$ , then find the smallest natural number $a$ such that $\large \tau(ah(\tau(a)))$ special .