# Thirty-One (31)

Online Roulette Guide

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The number 31 is a black number on the roulette wheel that sits between the black numbers 14 and 9 on a European table and 18 and 19 on an American table.

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### What´s So Special about 31 then?

It’s a prime number- one that can only be divided by one and itself, like 17 and 19- traditionally popular numbers on a roulette wheel (although we are scratching our heads wondering why).

Maybe subconsciously players are attracted to primes as they seem special?

31 is actually known as the 4th lucky prime in maths circles. The Lucky Numbers on a roulette wheel are as follows:
1, 3, 7, 9, 13, 15, 21, 25, 31, 33.

Remember, by Lucky Number we are referring to the mathematical label. We are not saying that somehow these numbers are more fortunate or that they come up more often! It’s a mathematical concept.

Lucky numbers are basically generated by listing out all the odd numbers: 1, 3, 5, 7, 9, 11, 13, etc, …. The first odd number after 1 is three, so you take out every third number from the list: 1, 3, 7, 9, 13, 15, 19, …. The first odd number bigger than 3 in the list is 7, so take out every seventh number: 1, 3, 7, 9, 13, 15, 21, 25, 31, 33….

You also get numbers that are lucky primes, of which 31 is a member. Lucky Primes on a roulette wheel are 1,3,7,13,31.

Another cool thing about the number 31?

These numbers are all prime numbers: 31, 331, 3331, 33331, 333331, 3333331, and 33333331.

### How Do I Bet on 31?

You can cover the individual number, of course, but if you want more table coverage, you are going to need to employ a bet like the even number bets (cover it with black, odd or high numbers) or go for a 2:1 pay out on either the bottom column or the 3rd dozen.

Inside bets like split bets (2 numbers), corner bets (4), street bets (3) and 6 number bets can all be used to cover 31 while hedging your bets on other numbers.

If you really fancy your chances on 31, you might want to try a roulette complete bet on 31 which will cover all of the Inside Bets on the number. If the ball drops in the 31 pocket, you get a big pay off, but if it doesn’t hit the number or the close zone surrounding it, it can be expensive!

We often cover this number with a Black Splits bet which you will find on some of the more premium roulette games. The number 31 is also one of the Orphelins – a group of numbers on a French or European table that make up the rest of the numbers after you have taken the Voisins and Tiers out. I literally means the Orphans.

### Who Was Born on the 31st? Anyone Famous?

Plenty of people! Justin Timberlake (come on, he is famous- the guys got so many followers on Twitter, they could be a medium sized country). JK Rowling was born on July 31st and so was Franz Schubert, the famous Austrian composer.

And guess who else? None other than Christopher Columbus and John Keats. I rest my case- some pretty famous people were born on the 31st.

As a date, October 31st is pretty famous as Halloween, of course, celebrated on the eve of All Hallows’ Day.

### What else can we say about 31?

31 is the atomic number of gallium- not one of the better known elements- it has the symbol Ga. Gallium is a soft, silvery blue metal at standard temperature and pressure- it doesn’t occur freely in nature.

If you are a star gazer, you might know about Messier object M31, which is a magnitude 4.5 galaxy in Andromeda, more commonly known as the Andromeda Galaxy. You can see it with the naked eye in a dark sky.

To find it, you just need to find the constellation Cassiopeia which points directly to the Andromeda galaxy. One half of the W of Cassiopeia is more sharply arrow shaped than the other half. This deeper arrow handily points to the Andromeda galaxy!

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### Summary

There’s only really one thing left to say about the number 31. Your odds of landing it are exactly the same as any other number on the roulette wheel. I know- we are stating the obvious, but we wanted to make sure you knew!