This post is an offshoot of this earlier MSE question.
According to this Wikipedia page:
Grun $1952$ proved that the smallest prime factor $p_1$ (of an odd perfect number $N$) is $< \frac{2\omega(N)}{3} + 2$ (where $\omega(N)$ is the number of distinct prime factors of $N$), and Perisastri $1958$ published the same result.
My question is: Does anybody here know the details of this result of Grun's? I mean, would you be able to reproduce Grun's proof here?
Thanks!