Let $\sigma_1$ be the classical sum-of-divisors function.
Let $$D(x) = 2x - \sigma_1(x)$$ be the deficiency of $x$.
Let $\varphi(x)$ denote the Euler totient.
Here is my question:
For what numbers $x$ is $D(x) = 2x - \sigma_1(x)$ equal to $\varphi(x)$?
Trivially, $x=1$ answers my question. But are there any others?