Warren Buffett is a big fan of Sirius XM Holdings (SIRI 2.58%). Or, at least someone on his investment team is.

Buffett's holding company now owns around $2.4 billion in Sirius XM shares, equal to roughly 30% of the total shares outstanding. Buffett's involvement alone is triggering many investors to pay closer attention. Right now, there are two numbers I've got my eye on that could signal that shares are a screaming buy.

1. Sirius XM Holdings is generating a ton of cash

Sirius XM reported earnings this week, and while accounting profits were once again in the negative, free cash flow ballooned to more than $500 million. That's an annual run rate of $2 billion -- a huge amount, given that the company's total market cap is only $8.1 billion.

Of course, the company isn't generating this sum every single quarter. But in general, Sirius XM does throw off a lot of cash as a business. Over the past 12 months, it generated roughly $1 billion in free cash flow. Just paying attention to accounting profits -- which have been negative in each of the past two quarters -- hides this financial reality.

SIRI Net Income (TTM) data by YCharts

Why is Sirius XM posting such big net losses while still maintaining high levels of free cash flow?

Its subscriber base is gradually falling, dropping by nearly 300,000 over the past year. However, the biggest issues have been purely related to accounting. Last quarter, for example, it posted a net loss, largely due to a $3.4 billion non-cash impairment charge related to restating the value of goodwill on its balance sheet.

These are largely one-time accounting maneuvers, meaning profits should swing positive again over the coming quarters. Next, we'll see how that comes into play.

2. Shares are undeniably cheap across several metrics

Most analysts expect Sirius XM to regain profitability fairly soon. On a forward basis -- that is, based on what analysts expect the company to earn next year -- shares trade at just 7.6 times earnings.

Due to persistently high free cash flow generation, Sirius stock currently trades at an 11.6% free cash flow yield. That free cash flow generation has supported major share repurchases but also delivers a current dividend yield of nearly 4.5%.

SIRI PE Ratio (Forward) data by YCharts

In the long term, Sirius XM does face some serious headwinds. Remote work has put a dent in subscriber growth, as many potential customers are no longer commuting regularly in their vehicles. Mounting competition from other streaming services continues to threaten the company's ability to attract and sustain its subscriber base.

However, in the most recent quarter, the company added nearly 150,000 new subscribers, bringing its total subscriber base up to 33 million. Even if the company reverts to losing 1% to 2% of its subscribers per year, the company should still have no issue generating ample free cash flows, which it can then use to improve its competitive positioning or redirect it back to shareholders.

There are two paths forward right now.

Management can continue with cost-cutting efforts, turning the company into a cash flow machine that tries to divert as much cash as possible to shareholders through share buybacks and dividend payments. Or it can attempt to reinvest heavily to compete in what otherwise is a very crowded industry.

I'm hoping for the former, in which case shares are so cheap, with such elevated cash flow generation, that it would be hard to argue against the company as an investment option. But if management starts burning through shareholder capital in an attempt to compete against better-financed competitors like Spotify, I'll be quickly moving to the sidelines.