  Let $\omega^*(n)$ be the number of primes $p$ such that $p-1$ divides $n$.
Recently, R. M. Murty and V. K. Murty proved that $$x(\log\log
x)^3\ll\sum_{n\le x}\omega^*(n)^2\ll x\log x.$$ They further conjectured that
there is some positive constant $C$ such that $$\sum_{n\le x}\omega^*(n)^2\sim
Cx\log x$$ as $x\rightarrow \infty$. In this short note, we give the correct
order of the sum by showing that $$\sum_{n\le x}\omega^*(n)^2\asymp x\log x.$$
