The Riemann hypothesis is a conjecture that the Riemann zeta function has its zeros only at the negative even integers and complex numbers with real part $\frac{1}{2}$. The Riemann hypothesis is considered by many to be the most important unsolved problem in pure mathematics. Let $\sigma(n)$ denote the sum-of-divisors function $\sigma(n)=\sum_{d \mid n} d$. An integer $n$ is perfect if $\sigma(n)=2 \cdot n$. It is unknown whether any odd perfect numbers exist. Leonhard Euler stated: ``Whether $\ldots$ there are any odd perfect numbers is a most difficult question''. We require the properties of superabundant numbers, that is to say left to right maxima of $n \mapsto \frac{\sigma(n)}{n}$. We also use Robin's criterion and Ramanujan's old not...