In finite Galois extensions $k_1,...,k_r$ of $\mathbf{Q}$ with pairwise coprime discriminants the integral and the prime divisors subject to the condition $N_{k_1/\mathbf{Q}}{𝔞}_r=\cdots =N_{k_r/\mathbf{Q}}{𝔞}_r$ are equidistributed in the sense of E. Hecke.

A natural number $n$ is said to be a $(k,r)$-integer if $n=a^{k}b$, where $k>r>1$ and $b$ is not divisible by the $r$th power of any prime. We study the distribution of such $(k,r)$-integers in the Piatetski-Shapiro sequence $\left\{\lfloor n^c\rfloor \right\}$ with $c>1$. As a corollary, we also obtain similar results for semi-$r$-free integers.

In this paper, we give a new upper-bound for the discrepancy$$D\left(N\right):=\underset{0\le \gamma \le 0}{sup}|\sum _{\genfrac{}{}{0pt}{}{p\le /N}{\left\{p^{\alpha }\right\}\le \gamma }}1-\pi \left(N\right)\gamma |$$for the sequence $\left(p^{\alpha }\right)$, when $5/3\le \alpha \>3$ and $\alpha \ne 2$.

Let $\left[x\right]$ be an integer part of $x$ and $d\left(n\right)$ be the number of positive divisor of $n$. Inspired by some results of M. Jutila (1987), we prove that for $1<c<\frac{6}{5}$, $$\sum _{n\le x}d\left(\left[n^c\right]\right)=cxlogx+(2\gamma -c)x+O\left(\frac{x}{logx}\right),$$ where $\gamma$ is the Euler constant and $\left[n^c\right]$ is the Piatetski-Shapiro sequence. This gives an improvement upon the classical result of this problem.

There exist infinitely many integers $n$ such that the greatest prime factor of $n^2+1$ is at least $n^{6/5}$. The proof is a combination of Hooley’s method – for reducing the problem to the evaluation of Kloosterman sums – and the majorization of Kloosterman sums on average due to the authors.