Billionaires are obviously ambitious, smart, and very, very, very lucky. There are, however, some surprisingly common traits among them. Here are the trends that presented themselves.

The most common professions among the parents of American billionaires were engineer, accountant, and small-business owner – all math-related careers. They have passed on the mathematical prowess to their offspring, as such prowess is often hereditary. Math and becoming a billionaire are intertwined.

Learning the ropes of investment banking, trading, or asset management at Goldman Sachs seems to have been a de rigueur training for 10 percent of all billionaire tycoons whose fortunes are in finance.

Another common trait is M.B.A. from a top school, especially ‘from Harvard, as did 19 of the self-made entrepreneurs on the Forbes 400. Another 19 took home M.B.A.s from Stanford, Columbia or the University of Pennsylvania’s Wharton School of Business.’

Failure seems to be the biggest commonality among billionaires. Their business acumen and attention to detail are results of tremendous failure they experienced early in their careers.

Now, for more whimsical common ground: more than 10 percent ‘of the 380 self-made American tycoons who have appeared on the Forbes list of the World’s Billionaires in the past three years, 42 were born in September–more than in any other month.’ What’s uncanny, ‘close to 15% of the self-made American moguls on the Forbes 400 never finished college. Many of the list’s drop-outs made their fortunes in tech, including Bill Gates (Microsoft), Steve Jobs (Apple), Michael Dell (Dell), Larry Ellison (Oracle) and Mark Zuckerberg (Facebook).’

Via Forbes-Yahoo