--description--

A number consisting entirely of ones is called a repunit. We shall define $R(k)$ to be a repunit of length $k$.

For example, $R(10) = 1111111111 = 11 × 41 × 271 × 9091$, and the sum of these prime factors is 9414.

Find the sum of the first forty prime factors of $R({10}^9)$.

--hints--

largeRepunitFactors() should return 843296.

assert.strictEqual(largeRepunitFactors(), 843296);

--seed--

--seed-contents--

function largeRepunitFactors() {

  return true;
}

largeRepunitFactors();

--solutions--

// solution required