WASHINGTON - Americans are getting older, but not this old: Social Security records show 6.5 million people in the U.S. have reached age 112.

Only a few could possibly be alive. As of the fall, there were only 42 people known to be that old in the entire world.

But the Social Security Administration does not have death records for millions of these centenarians, the oldest of whom was born in 1869, according to a report from the agency's inspector general.

Only 13 of the people are still getting Social Security benefits, the report said. But the Social Security numbers of others are still active and could be used to report wages, open bank accounts, obtain credit cards, or claim fraudulent tax refunds.

"That is a real problem," said Sen. Ron Johnson (R., Wis.) "When you have a fake Social Security number, that's what allows you to fraudulently do all kinds things, claim things like the earned income tax credit or other tax benefits."

Johnson is chairman of the Senate Committee on Homeland Security and Governmental Affairs, which plans a hearing Monday on problems with death records maintained by the Social Security Administration.

The agency said it was working to improve the accuracy of its death records. But it would be costly and time-consuming to update 6.5 million files that were generated decades ago, when the agency used paper records, said Sean Brune, a senior adviser to the agency's deputy commissioner for budget, finance, quality, and management.

"The records in this review are extremely old, decades old, and unreliable," Brune said.

The internal watchdog's report did not document any fraudulent or improper payments to people using the Social Security numbers in question, but it raised red flags of the potential for fraud.

For example, nearly 67,000 of the numbers were used to report more than $3 billion in wages, tips, and self-employment income from 2006 to 2011, according to the report. One number was used 613 different times. An additional 194 numbers were used at least 50 times each.

People in the country illegally often use fake or stolen Social Security numbers to get jobs and report wages, as do other people who do not want to be found by the government. Thieves use stolen Social Security numbers to claim fraudulent tax refunds.

The IRS estimated it paid out $5.8 billion in fraudulent tax refunds in 2013 because of identity theft.

The Social Security Administration generates a list of dead people to help public agencies and private companies know when numbers are no longer valid. The Death Master File includes names, Social Security numbers, and birth and death dates.

It is widely used by employers, financial firms, credit reporting agencies, and security firms. Federal agencies and state and local governments rely on it to police benefit payments.

But none of the 6.5 million people cited in the inspector general's report was on the list.