Prime Factors of 2016

What is the least positive integer that, when multiplied by 2016, yields a product which is a perfect square ?


The answer is 14.

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4 solutions

Paul Hindess
Dec 24, 2016

2016 = 2 5 × 3 2 × 7 1 2016 = 2^5 \times 3^2 \times 7^1 . Observing that we need all powers to be even in order for it to be a square number, we multiply by 2 × 7 = 14 2\times 7=14 .

I don't understand. Please elaborate. I don't even understand the question.

Simon Cochrane - 4 years, 4 months ago
Mohammad Khaza
May 7, 2017

√2016=12√14 so,12×〖14〗^2 will be the perfect square number.the least positive integer is 14

good explanation

Halima Tahmina - 4 years ago

thanks.your comment inspired me

Mohammad Khaza - 4 years ago
Marcus Muenze
Apr 6, 2019

We know that k × 2016 = a 2 \sqrt{k \times 2016} = \sqrt{a^{2}} . LHS and RHS are both Natural Numbers. K is the smallest integer we are looking for. Then a = 4 × 3 × k × 2 × 7 . a = 4 \times 3 \times \sqrt{k} \times \sqrt{2 \times 7}. For k = 14 a a is a Natural Number. Since Prime factorization of 14 = 2 × 7 14 = 2 \times 7 , there is no smaller k.

Sanam Amin
Jan 5, 2017

sq(2016) = 12 * sq(7) * sq(2) So, all you have to do is add a root 2 and root 7 to 2016, which means 2016 * 7 * 2 = 28224, then divide 28224 by 2016 because 2016 * x = 28224, and x = 14.

How do you even begin to solve this ? "all we have to do is add a root 2 and root 7" ??? what process is this ?

Simon Cochrane - 4 years, 4 months ago

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sq(2016) = sq(1008) * sq(2) = sq(504) * 2 = sq(252) * sq(2) * 2 = sq(126) * 4 = sq(63) * sq(2) * 4 = sq(21) * sq(3) * sq(2) * 4 = sq(7) * 3 * sq(2) * 4 = 12 * sq(7) * sq(2). When you take the root of a perfect square, you get an integer. Since we have 12 * sq(7) * sq(2), we would need to multiply sq(2016) by sq(7) and sq(2) to make it a perfect square, or multiply 2016 by 7 * 2, or 14. This works out to 28224, or 168^2. You need to relax; just because you don't understand doesn't mean it's wrong.

Sanam Amin - 4 years, 2 months ago

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