# What’s your least favourite number?

Read about our least favourite numbers in this collection from issue 5! Mathematics doesn’t always involve working with numbers, but they crop up frequently enough for us to have developed some strong emotional responses to specific ones! Throughout the pages of Chalkdust Issue 5 we shared some of the numbers that we really dislike, and here we’ve collected them together. Do you have a least favourite number? Let us know at the bottom of this post.

## The golden ratio, $\varphi$ (Tom Rivlin)

All the ancients revered it. It holds the secret to beauty and art itself. All of nature is based on it. Its proportions are perfection itself. It has magical properties…

…except none of that is true. It’s just half of one plus root five. It’s the solution to a quadratic equation. It’s the limiting ratio of a Fibonacci sequence; the growth factor of a logarithmic spiral. It appears in some places in nature. It appears nowhere in human anatomy. It was used by some classical artists. It has some neat mathematical properties. Whoever runs the golden ratio’s PR department is doing a great job, but the golden ratio needs to get over itself. The hype ruins it.

Rating: $\mathbf{0/10}$

## Googolplex (Belgin Seymenoğlu)

Ever heard of googol ($10^{100}$)? You have? What about googolplex ($10^\text{googol}$)? No?
Well, while a googol is a one followed by a hundred zeroes, a googolplex is a one followed by googol zeroes. So it can be written as
$$10^{10^{100}},$$
which is not nice at all. Most calculators already can’t handle googol, which is bad enough, but googolplex takes it even further. One morning I asked my computer to print googolplex; it never got back to me.

Rating: $\mathbf{\log_{10}{(\log_{10}{(10))}} / 10}$

## $-1/12$ (Matthew Scroggs)

What is $1+2+3+4+5+\cdots$? Obviously, you’ll get to $+\infty$. If anyone ever tells you that the answer is –1/12, they are being silly.

Rating: $\mathbf{-12/10}$

## NaN (Pietro Servini)

My least favourite number is NaN, which can look something like the figure below. I very much
disapprove of this number as it usually means that there’s yet another mistake in my code.

Rating: $10/0$

## $2016$ (Aryan Ghobadi)

I mean, it’s just a horrible number! Worst prime factorisation ever: 5 powers of 2 and just 1 power of 7?!? It’s insanity!

Rating: $\mathbf{7/2016}$

## $17$ (Alex Doak)

My favourite number used to be 17. However, it was brought to my attention by a slightly ‘trendier’ friend that a variety of online surveys place 17 as the ‘most common random number’. Turns out I’m more mainstream than previously believed.

Rating: $\mathbf{1.7/10}$

## $5040$ (Rafael Prieto Curiel)

My least favourite number is 5,040. Why? It happens that 7! = 5040, and so it has loads of divisors (60 in total). It is therefore known as a  “colossally abundant number”…. not pretentious at all! Since it has so many divisors, Plato suggested in his book Laws that it should be used in for the size of an army, since it can be divided evenly into smaller parts. So what? You’d rather have an army of 5,040 instead of an army of 11,113 just because the latter is a prime number?

Rating: $\mathbf{300/5,040}$

## $27 000$ (Yiannis Simillides)

My least favourite number is 27,000, because that is the amount of money I now owe the government.

Rating: £27,000/my pocket

## $\epsilon$ (TD Dang)

I hate $\epsilon$, but only a small amount.

Rating: $\mathbf{\epsilon/}$N