UnitedHealth is a solid dividend stock that you can buy and forget about.Are you looking for a good dividend stock to own? You might want to take a closer look at UnitedHealth Group (UNH -1.44%). It's a top healthcare company to invest in, and while its yield may not look all that high, it can make for a solid investment, especially if you hang on to it for the long term.There are plenty of great reasons why dividend investors should buy this underrated stock today. Here are three worth mentioning:1. United ...