The S&P 500 is offering investors a paltry dividend yield of 2.1%, which isn't appealing to investors looking for income. But here are three stocks with dividend yields of more than 4%. All three are the highest-yielding Dividend Aristocrats, which are stocks with 25-plus years of consecutive dividend increases.

Better yet, the Dividend Aristocrats index has outperformed the market by 3.4 percentage points a year on average over the past decade, according to S&P Global. (See all 50 Dividend Aristocrats here.)

Investing in the highest-yielding Dividend Aristocrats combines the safety and stability that comes with 25-plus years of consecutive dividend increases with dividend yields that are more than twice as high as the S&P 500's dividend yield.

In short, the highest-yielding Dividend Aristocrats provide something extremely rare: income and stability.

This isn't to say these are no-risk stocks, as higher-yielding stocks tend to come with more risk. Two of the three highest-yielding Dividend Aristocrats have struggled recently, though their long-term prospects remain bright.

1. HCP (HCP - Get Report)

The company is the highest-yielding Dividend Aristocrat, with a dividend yield of 5.9%, and it has paid increasing dividends for 31 consecutive years.

HCP is also the only real estate investment trust that is a Dividend Aristocrat.

REITs are required by law to pay out 90% or more of their profits as distributions to shareholders. This makes it difficult for REITs to sustain higher dividends year after year, which makes the fact that HCP is a Dividend Aristocrat even more impressive.

HCP is a health care REIT that operates more than 1,000 properties in the British Isles and U.S. The health care industry is historically fairly recession-resistant, which has helped HCP's stability over the past three decades.

Senior housing is the company's single largest earnings driver. This is good news for long-term shareholders because as baby boomers continue to age, the number of elderly will rise, creating a built-in growth driver for HCP.

Nevertheless, HCP has struggled recently. The company's skilled-nursing facilities under the ManorCare name are no longer profitable due to changes in the mix from traditional Medicare to managed-care plans.

HCP's management has responded by planning to spin off the poorly performing ManorCare business unit. The goal is to increase stability at HCP, while allowing investors to choose how much exposure they want to the ManorCare segment.

The spinoff will boost HCP's exposure to senior care to 54% of income from 40%.

HCP's short-term struggles don't offset its long-term growth prospects or its high dividend yield.

There is the possibility that HCP will cut its dividend when it spins off ManorCare. Regardless, dividends will likely rise over the long run as the company benefits from aging populations.

2. AT&T (T - Get Report)

This company is the second-highest-yielding Dividend Aristocrat, with a 4.4% dividend yield. It is also the largest telecommunication company in the U.S. based on its $267.27 billion market capitalization

AT&T has paid increasing dividends for 32 consecutive years and has a payout ratio of 82%. AT&T can safely maintain a high payout ratio because its operations are so stable.

Not only are operations stable, which provides safety for dividend investors, but AT&T is also realizing faster growth than one would expect from a mega-cap telecom company.

The company saw operating income growth of 13.6% in its latest second quarter. Adjusted earnings per share grew at a more modest 2.9% year over year.

AT&T's double-digit operating income growth year over year is a result of its acquisition of DirecTV.

"Cost synergies are ahead of target. We've added nearly 1 million DirecTV subscribers since the acquisition, and our new video streaming services are scheduled to roll out later this year," Chief Executive Randall Stephenson said in a second-quarter report statement. 

"We plan to serve every segment of the video industry and offer customers their favorite content virtually wherever and whenever they want it," he said.

AT&T's growth will come from data usage among its wireless customer base. The company is also realizing synergies with its DirecTV acquisition.

In addition, the company is expanding into Mexico, where it has 10 million wireless subscribers. The company's expansion into Mexico with its wireless plans and Latin America with its DirecTV acquisition opens up a long growth runway for the company.

AT&T stock is trading for a forward price-to-earnings ratio of 14.4. The company offers investors a rare investment opportunity: a safe, consistently high-paying dividend stock with growth potential.

3. Chevron (CVX - Get Report)

This company is the third-highest-yielding Dividend Aristocrat based on its 4.2% dividend yield. Chevron is also the second-largest oil and gas corporation in the U.S., behind ExxonMobil.

Chevron, which can trace its origins back to 1879, is one of just 32 blue-chip stocks in the S&P 500 with 100-plus-year operating histories and 3%-plus dividend yields. In short, the company has a long history of success.

Recent history hasn't been so kind to Chevron.

The company's upstream operations are posting deep losses due to low oil prices. Chevron's upstream division has posted losses of $3.92 billion through the first half this year.

Fortunately, the company's downstream operations have done well, generating $2.01 billion in profits in the first half. Still, the company is losing money.

So can Chevron really continue to pay increasing dividends?

If history is any indication, the company will do everything in its power to keep its 28-year dividend growth streak alive. 

Analysts expect a modest 2% dividend increase in the fourth quarter to keep the dividend increase streak alive.

Looking at Chevron's cash flow and balance sheet reveals that the company has a lot of cash in reserve and access to debt to outlast low oil prices.

Chevron pays about $2 billion a quarter in dividends or about $4 billion over six months. The company has generated $5.76 billion in operating cash flow over the past six months, excluding changes in working capital.

This leaves $1.76 billion left after dividends through the first half of the year. Chevron has also realized $10.29 billion in capital expenditures, excluding non-cash expenditures from affiliate interests.

If oil prices stay where they are and Chevron's operations remain constant over the second half, the company will need $8.53 billion in cash to bridge the shortfall.

The company has $9.08 billion in cash and marketable securities on its balance sheet. Additionally, and more importantly, the company still has plenty of access to debt capital.

Chevron has added $6.54 billion in net debt over the past 12 months to its balance sheet.

The company will likely continue tapping debt markets to finance its operations until oil prices rise. The company has an AA- rating from Standard & Poor's and an Aa2 rating from Moody's.

It is very likely that Chevron is able to continue financing its operations through debt and possibly additional asset sales while it waits for oil prices to recover.

In the meantime, investors get paid to wait with the company's 4.2% dividend yield.

Make no mistake: Chevron does carry some risk of a dividend reduction if oil prices stay low for years. The company's management is committed to increasing dividends, however.

Chevron carries more risk than many of the lower-yielding Dividend Aristocrats, but it compensates for this risk with a higher dividend yield.

This article is commentary by an independent contributor. At the time of publication, the author held no positions in the stocks mentioned.