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Triffle Numbers

 Published on Sunday, 26th January 2020, 10:00 am; Solved by 143;
Difficulty rating: 80%

Problem 699

Let $\sigma(n)$ be the sum of all the divisors of the positive integer $n$, for example:
$\sigma(10) = 1+2+5+10 = 18$.

Define $T(N)$ to be the sum of all numbers $n \le N$ such that when the fraction $\frac{\sigma(n)}{n}$ is written in its lowest form $\frac ab$, the denominator is a power of 3 i.e. $b = 3^k, k > 0$.

You are given $T(100) = 270$ and $T(10^6) = 26089287$.

Find $T(10^{14})$.