The U.S. Justice Department said Friday that Genesis Health Inc., a major nursing home operator based in Kennett Square, will pay $53.6 million to settle six federal lawsuits and investigations alleging that companies and facilities acquired by Genesis billed the government for "medically unnecessary therapy and hospice services, and grossly substandard nursing care."

The final settlement is slightly larger than the $52.7 million Genesis estimated last summer, when the company disclosed an agreement in principal to settle the allegations, some of which date back to 2003.

The investigations involved allegations that Genesis units of companies acquired since 2012, including Skilled Healthcare Group Inc. and Sun Healthcare Group Inc., improperly billed the government for hospice services in Nevada, provided inadequate staffing at some facilities from 2005 through 2013, and violated Medicare rules for physical therapy at two subsidiaries.

The settlement includes $9.67 million for the whistle blowers who brought the cases to the government's attention.