Japt, 13 12 11 bytes

sw
*V/yU ²

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Explanation

Implicit input of integer U. The empty line at the beginning, prevents the following line from overwriting U

sw

Convert U to a string (s), reverse it (w), convert back to an integer and assign to variable V.

*V

Multiply U by V.

/

Divide.

yU

GCD of V and U.

²

Squared. Implicit output of resulting integer.

Alternative, 13 bytes

Just because I like being able to use N.

NpUsw)mxNry)×

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