Perfect Numbers in PHP
Determine if a number is perfect, abundant, or deficient based on Nicomachus' (60  120 CE) classification scheme for natural numbers.
1  exercism fetch php perfectnumbers

Perfect Numbers
Determine if a number is perfect, abundant, or deficient based on Nicomachus' (60  120 CE) classification scheme for natural numbers.
The Greek mathematician Nicomachus devised a classification scheme for natural numbers, identifying each as belonging uniquely to the categories of perfect, abundant, or deficient based on their aliquot sum. The aliquot sum is defined as the sum of the factors of a number not including the number itself. For example, the aliquot sum of 15 is (1 + 3 + 5) = 9

Perfect: aliquot sum = number
 6 is a perfect number because (1 + 2 + 3) = 6
 28 is a perfect number because (1 + 2 + 4 + 7 + 14) = 28

Abundant: aliquot sum > number
 12 is an abundant number because (1 + 2 + 3 + 4 + 6) = 16
 24 is an abundant number because (1 + 2 + 3 + 4 + 6 + 8 + 12) = 36

Deficient: aliquot sum < number
 8 is a deficient number because (1 + 2 + 4) = 7
 Prime numbers are deficient
Implement a way to determine whether a given number is perfect. Depending on your language track, you may also need to implement a way to determine whether a given number is abundant or deficient.
Running the tests

Go to the root of your PHP exercise directory, which is
<EXERCISM_WORKSPACE>/php
. To find the Exercism workspace run1
% exercism debug  grep Workspace

Get PHPUnit if you don't have it already.

Execute the tests:
1
% ./phpunit.phar perfectnumbers/perfectnumbers_test.php
Source
Taken from Chapter 2 of Functional Thinking by Neal Ford. http://shop.oreilly.com/product/0636920029687.do
Submitting Incomplete Solutions
It's possible to submit an incomplete solution so you can see how others have completed the exercise.