Check is object exists in property

I am trying to see if the property contains another object.

I have this:

{
  "prop1": "value",
  "prop2": "value",
  "prop4": "value",
  "prop5": {
      "innerprop1": "value",
      "innerprop2": "value"
  },
  "prop6": {
      "innerprop3": "value",
      "innerprop4": "value"
  }
}

I want to know if any of the properties has an object in it.

Any help would be appreciated.