--- id: 5900f5331000cf542c510046 title: 'Problem 455: Powers With Trailing Digits' challengeType: 5 forumTopicId: 302129 dashedName: problem-455-powers-with-trailing-digits --- # --description-- Let f(n) be the largest positive integer x less than 109 such that the last 9 digits of nx form the number x (including leading zeros), or zero if no such integer exists. For example: f(4) = 411728896 (4411728896 = ...490411728896) f(10) = 0 f(157) = 743757 (157743757 = ...567000743757) Σf(n), 2 ≤ n ≤ 103 = 442530011399 Find Σf(n), 2 ≤ n ≤ 106. # --hints-- `euler455()` should return 450186511399999. ```js assert.strictEqual(euler455(), 450186511399999); ``` # --seed-- ## --seed-contents-- ```js function euler455() { return true; } euler455(); ``` # --solutions-- ```js // solution required ```