Solutions of d(n)=d(ϕ(n)) where n has four different prime divisors
Solutions of d(n)=d(ϕ(n)) where n has four different prime divisors
Abstract
For a positive integer n, let d(n), ϕ(n) and ω(n) denote the number of positive divisors of n, the Euler's phi function of n and the number of different prime divisors of n, respectively. In this paper, we focus on positive integers n such that d(n)=d(ϕ(n)) and ω(n)=4.
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