LONDON -- To much consternation, insurance giant Aviva (AV 0.60%) (AVVIY 0.17%) recently announced a dividend cut. Since then, the share price has fallen by around 20%.

This decline has made the investment case for Aviva even more compelling.

I've compared Aviva with every other FTSE 100 company using two crucial valuation metrics: dividend yield and price-to-earnings (P/E) ratio. By my calculations, no other company is cheaper on both measures.

Remember that there should always be more to your investment research and decision-making than just a couple of statistics. However, the apparent cheapness of Aviva means that they are worth further research.

Low price
Aviva shares are currently trading just 10% off a three-year low. It is noteworthy that today, as the market is selling off, shares in Aviva are hardly changed. There are very few shareholders remaining that are motivated to sell. This suggests to me that in better markets, Aviva shares could do very well indeed.

Low P/E
According to my stats package, only two other shares in the FTSE 100 (Vedanta and Eurasian Natural Resources) are trading on a lower forward P/E than Aviva. Those shares operate in a sector that is currently facing turmoil from falling resources prices.

There is less risk to Aviva's business. Analysts expect earnings per share of 46.7 pence for 2014, meaning the shares currently trade on a 2014 P/E of just 6.3.

High yield
Aviva's recent dividend cut means that the yield on the shares is safer than it has been for a long time.

Aviva's chief executive, Mark Wilson, has been in the top job since the beginning of the year. After cutting the dividend at the first available opportunity, he will be staking his reputation on not cutting again.

Another 19 pence of dividends is expected for 2013, rising to 19.6 pence the year after. At today's share price that's a 2014 yield of 6.7%.

Share price outlook
The market seems particularly uncertain about Aviva's future. By the time that the company has reported another set of final results there may be greater clarity on the progress that Mr Wilson is making with the business. Opportunities to buy companies at low valuations are often short-lived. If you wait for certainty then the shares could rise significantly without you.

Fortunately, Aviva is not the only attractive income stock in the FTSE 100 today. Stock-pickers here at the Motley Fool have identified another share that they believe could be an even better income investment. This company has a dominant role in its markets and in the last five years has been increasing its dividend by almost 9% a year. To learn more about this company, get the free report "The Motley Fool's Top Income Share for 2013." Just click here for your copy of this totally free report today.