**József Sándor**

Notes on Number Theory and Discrete Mathematics

Print ISSN 1310–5132, Online ISSN 2367–8275

Volume 26, 2020, Number 3, Pages 1–4

DOI: 10.7546/nntdm.2020.26.3.1-4

**Full paper (PDF, 159 Kb)**

## Details

### Authors and affiliations

József Sándor

*Department of Mathematics, Babes-Bolyai University
Cluj-Napoca, Romania
*

### Abstract

We study the equation *φ*(*n*) + *d*(*n*) = *n*, and prove related new inequalities.

### Keywords

- Arithmetic function
- Inequality

### 2010 Mathematics Subject Classification

- 11A25

### References

- Sándor, J., Mitrinovic, D., & Crstici, B. (2005).
*Handbook of Number Theory*, Vol. I, Springer. - Sándor, J., & Kovács, L. (2008). A note on the arithmetical functions
*d*(*n*) and*σ*(*n*).*Octagon Math. Mag*., 16 (1), 270–274. - Sándor, J. (2010). Two arithmetic inequalities.
*Advanced Studied Contemporary Mathematics*, 20 (2), 197–202. - Sándor, J. (2014). On certain inequalities for
*σ, φ, ψ*and related functions.*Notes on Number Theory and Discrete Mathematics*, 20 (2), 52–60. - Sándor, J.(1989). Some diophantine equations for particular arithmetic functions.
*Seminarul de Teoria Stucturilor*, 53, 1–10 (in Romanian).

## Related papers

- Sándor, J. (2014). On certain inequalities for
*σ, φ, ψ*and related functions.*Notes on Number Theory and Discrete Mathematics*, 20 (2), 52–60. - Sándor, J., & Bhattacharjee, S. (2022). On certain equations and inequalities involving the arithmetical functions
*φ*(*n*) and*d*(*n*).*Notes on Number Theory and Discrete Mathematics*, 28(2), 376–379. - Sándor, J. (2023). On certain equations and inequalities involving the arithmetical functions
*φ*(*n*) and*d*(*n*) – II.*Notes on Number Theory and Discrete Mathematics*, 29(1), 130-136.

## Cite this paper

Sándor, J. (2020). On the equation *φ*(*n*) + *d*(*n*) = *n* and related inequalities. *Notes on Number Theory and Discrete Mathematics*, 26 (3), 1-4, DOI: 10.7546/nntdm.2020.26.3.1-4.