Retiring with $1 million is a good target for many investors. With that amount of savings built up, investors can dip into that to help fund their lifestyles while also generating some decent dividend income. For example, if you invested $1 million across stocks paying 5% yields, that would result in $50,000 in recurring annual income.

Getting to $1 million can be a challenge, but one stock that can help get you there is UnitedHealth Group (UNH -0.04%). Year to date, its shares are up 8% while the S&P 500 has declined by 20%. Here's why the stock can make an excellent pillar to build your portfolio around and a key part of your retirement plan.

The company's business is resilient

Although inflation is hampering many businesses, UnitedHealth isn't one of them.

On Oct. 14, UnitedHealth reported its latest earnings numbers. In the third quarter (ended Sept. 30), its sales totaled $80.9 billion and rose 12% year over year. The company's customer base has been increasing, with UnitedHealthcare reporting a 185,000 increase in people served in the domestic market this past quarter. And those numbers are likely to continue rising given the aging of the U.S. population; by 2034, there will be more people age 65 and over than there are children under the age of 18.

UnitedHealth's performance was strong enough this past quarter for the company to justify raising its guidance for the year. The business now projects its diluted earnings per share to come in between $20.85 to $21.05, up from its previous forecast of $20.45 to $20.95.

The company is pursuing growth opportunities

At a market cap of $500 billion, UnitedHealth is already a top company in the healthcare industry. But that doesn't mean the business is standing pat. The company remains focused on growth, and that is a crucial ingredient for a stock to rise in value in the long term and generate strong returns for investors.

In March, UnitedHealth announced plans to buy in-home healthcare company LHC Group for $5.4 billion. And this month, it announced the completion of its $8 billion acquisition of health tech company Change Healthcare.

As of the end of September, UnitedHealth reported $38.8 billion in cash and cash equivalents. And with the business consistently generating free cash flow, UnitedHealth's coffers will only get stronger over time. UnitedHealth's strong financials put it in excellent shape to continue pursuing growth while also expanding its dividend payments.

UnitedHealth's dividend is great for long-term investors 

At first glance, investors may not think much of UnitedHealth's dividend. It only yields 1.2%, which is well below the S&P 500 average of 1.8%. But the dividend is underrated because over the past decade, the company has been generously increasing its payouts:

UNH Dividend Chart

UNH Dividend data by YCharts

Over the long run, as UnitedHealth continues to grow its bottom line, it will have room for more increases in its dividend. That means the dividend you're earning on your initial investment today could become much more significant down the road. The company's payout ratio currently sits at a modest 30% of profits.

Investors should buy and hold UnitedHealth stock for years

If you're investing for retirement and aiming to get your portfolio to $1 million, you'll want to hold multiple stocks to diversify and keep your risk low, but UnitedHealth is one investment that you should certainly consider making a cornerstone of that strategy. The company's strong financials, appetite for growth, and rising dividend are all reasons this can continue being a market-beating stock to own for the long haul.