Social Security is an essential part of most people's financial planning for retirement. But many people don't know everything they should about the Social Security program.

In the following video, Dan Caplinger, The Motley Fool's director of investment planning, looks at three Social Security secrets that few people know. Dan points out that only 70% of the program's 57 million beneficiaries are retired workers, with disabled workers, survivors, and dependents making up the remainder. He also notes that some state and local government workers don't participate in Social Security, instead having their own separate pension plans. Dan concludes with a reminder that divorced spouses can claim benefits under an ex-spouse's work history under certain circumstances, as long as they were married 10 years or more and meet other requirements.

Fool contributor Dan Caplinger and The Motley Fool have no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.