Problem 156. Parasitic numbers

Created by the cyclist

Solve Later

Test whether the first input x is an n-parasitic number: http://en.wikipedia.org/wiki/Parasitic_number. ( n is the second input.)

Examples:

parasitic(128205,4) ---> true

parasitic(179487,4) ---> true

parasitic(179487,3) ---> false

Solve

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Last Solution submitted on Jan 09, 2026

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@bmtran (Bryant Tran) on 1 Feb 2012

might be best to add a test case to guard against test suite hacking

John D'Errico on 30 Sep 2016

Far too few test cases. In fact, a serious issue with this problem is that there are too few parasitic numbers that will fit into even 64 bits for most values of n.

John D'Errico on 30 Sep 2016

I've added some test cases, that will make it a bit more difficult to game this problem.

JD on 7 Nov 2016

Cases 5 and 7 are identical, and I believe they are both wrong. 5 x 142857 = 714285. Isn't this a parasitic number? What am I missing?

Jess Stuart on 8 Feb 2017

Can the problem creator disqualify "solutions" that cheat? There should be a point penalty (-200) associated with cheating too.

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Problem 156. Parasitic numbers

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Last 200 Solutions

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Problem 156. Parasitic numbers

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Last 200 Solutions

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Solution Comments

Problem Recent Solvers312

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