The least integer whose multiplication with 588 leads to a perfect squ

The least integer whose multiplication with 588 leads to a perfect square is

2
3
4
7
This question was previously asked in
UPSC CAPF – 2013
A perfect square is an integer that is the square of an integer. In terms of prime factorization, a number is a perfect square if and only if all the exponents of its prime factors are even.
First, find the prime factorization of 588.
588 ÷ 2 = 294
294 ÷ 2 = 147
147 ÷ 3 = 49
49 ÷ 7 = 7
7 ÷ 7 = 1
So, the prime factorization of 588 is 2² × 3¹ × 7².

To make 588 a perfect square by multiplication, we need to multiply it by an integer such that all the exponents in the resulting prime factorization are even.
The exponents in 588 are: 2 (for prime 2), 1 (for prime 3), and 2 (for prime 7).
The exponents of 2 and 7 are already even.
The exponent of 3 is 1, which is odd. To make it even, we need to multiply by 3 raised to an odd power. The least such power is 1. So, we must multiply by at least 3¹.
Multiplying 588 by 3:
588 × 3 = (2² × 3¹ × 7²) × 3¹ = 2² × 3¹⁺¹ × 7² = 2² × 3² × 7².
The exponents are now 2, 2, and 2, which are all even.
The resulting number is (2 × 3 × 7)² = 42², which is a perfect square.
The least integer whose multiplication with 588 leads to a perfect square is 3.

A number is a perfect square if and only if all the exponents in its prime factorization are even.
To find the least multiplier to make a number a perfect square, find its prime factorization and multiply by the factors that have odd exponents, raised to the power of 1. For example, if the factorization is a³b²c⁵, you need to multiply by a¹c¹ to make the exponents even (a⁴b²c⁶).
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