freeCodeCamp/curriculum/challenges/english/08-coding-interview-prep/project-euler/problem-429-sum-of-squares-of-unitary-divisors.english.md

id, challengeType, isHidden, title, forumTopicId

id	challengeType	isHidden	title	forumTopicId
5900f5191000cf542c51002c	5	false	Problem 429: Sum of squares of unitary divisors	302099

Description

A unitary divisor d of a number n is a divisor of n that has the property gcd(d, n/d) = 1. The unitary divisors of 4! = 24 are 1, 3, 8 and 24. The sum of their squares is 12 + 32 + 82 + 242 = 650.

Let S(n) represent the sum of the squares of the unitary divisors of n. Thus S(4!)=650.

Find S(100 000 000!) modulo 1 000 000 009.

Instructions

Tests

tests:
  - text: <code>euler429()</code> should return 98792821.
    testString: assert.strictEqual(euler429(), 98792821);

Challenge Seed

function euler429() {
  // Good luck!
  return true;
}

euler429();

Solution

// solution required