$7928$ is obviously not a perfect square. Give reason.

$222222$ is obviously not a perfect square. Give reason.

$64000$ is obviously not a perfect square. Give reason.

$89722$ is obviously not a perfect square. Give reason.

$222000$ is obviously not a perfect square. Give reason.

$505050$ is obviously not a perfect square. Give reason.

Write a Pythagorean triplet whose one member is $6$.