“…As usual, let (p k ) k≥1 denote the increasing sequence of prime numbers, and let N k be the primorial integer of index k, the product of its k first terms. The Riemann Hypothesis (RH) claims that the nontrivial zeros of zeta function ζ(s) = n≥1 n −s are located on the critical line R(s) = 1 2 . Several equivalent formulations of RH appeared, but the one which interests us here is that in terms of arithmetic functions, here we cite the first papers of Gronwall [8], Nicolas [11] and Robin [13], followed by, for instance, Akbary [1], Caveney et al [6] and Lagarias [10].…”