## `numlib::invphi` -- the inverse of the Euler phi function

#### Introduction

`numlib::invphi(`n`)` computes all positive integers `i` with numlib::phi(i) = n.

#### Call(s)

`numlib::invphi(n)`

#### Parameters

`n` | - | a positive integer

#### Returns

a list of positive integer numbers.

#### Related Functions

`numlib::phi`

#### Example 1

We compute all numbers `i` with numlib::phi(i) = 500:

    >> s := numlib::invphi(500)

                           [625, 753, 1004, 1250, 1506]

Test for correctness:

    >> map(s, numlib::phi)

                             [500, 500, 500, 500, 500]

#### Changes

- new function

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