The global financial crisis was good for billionaires.
The combined fortune of the world's billionaires has more than doubled, to $6.5 trillion, from $3.1 trillion in 2009, according to Wealth-X and UBS Global Billionaire Census 2013. Their fortunes have grown by $226 billion in the past year alone.
The group's number also grew by 810 during the period, to 2,170.
(Read more: Asia shines as billionaire hot spot in 2013)
Their total wealth is now larger than the GDP of any country except that of the United States and China, and could fund the U.S. budget deficit until 2024, according to the report.
What else do we know about these billionaires?
Most are entrepreneurial men, and most of their money comes from private companies. They have an average of four homes and 2.1 kids, according to the report.
Of course, talking about the average billionaire is like talking about the average celebrity. It's tough to generalize.