From The Grapes of Math: How Life Reflects Numbers and Numbers Reflect Life, by Alex Bellos. Copyright © 2014 Alex Bellos. Excerpted with permission by Simon & Schuster.
One response to numbers is affection. After counting, calculating and quantifying with our numerical tools it is common to develop feelings for them. Jerry Newport, for example, loves some numbers like friends. I had not realized the depth of our collective number love, however, until I conducted an online experiment, asking members of the public to nominate their favorite numbers and explain their choices. I was taken aback not only by the level of interest—more than 30,000 people took part in the first few weeks—but also by the variety and tenderness of the submissions: 2, because the respondent has two piercings; 6, because the sixth track on the respondent’s favorite albums is always the best song; 7.07, since the respondent used to always wake up at 7:07 AM, and once her shopping added up to $7.07 in front of the cute cashier at her local shop; 17, because that’s how many minutes the respondent takes to cook rice; 24, because the respondent sleeps with her left leg kicked out like a 4 and her boyfriend sleeps like a 2 on his side; 73, known to fans of The Big Bang Theory as the ‘Chuck Norris of numbers’, because the main character, Sheldon Cooper, points out that it is the 21st prime number, and its mirror 37 is the 12th; 83, because it sounds good to exaggerate with, as in ‘I must have done it 83 times!’; 101, because it is the lowest whole number with an ‘a’ in it; 120, because it is divisible by 2, 3, 4, 5, 6, 8 and 10, providing the respondent with sufficient numbers to count up and down to get to sleep; 159, because it is the diagonal on a phone keyboard; 18,912, because its cadence makes it ‘the most beautiful sounding number in the world’; and 142,857, the phoenix number, because its first six multiples are well-ordered numerical anagrams of itself:
142857 × 1 =              142857
142857 × 2 =                  285714
142857 × 3 =                428571
142857 × 4 =                      571428
142857 × 5 =                        714285
142857 × 6 =                    857142
142857 × 7 =              999999
‘Having a favorite number means that you get a little buzz every time you happen to be sitting in seat 53 on a train, or notice that the time is 09:53,’ wrote one respondent. ‘I can’t think of a reason not to have a favorite number.’
With the caveat that the survey was voluntary and self-selecting, a bit of fun rather than rigorously undertaken academic research, the data revealed fascinating patterns in favorite number choices.
Firstly, the span of our number hug is huge: 1123 individual numbers from 30,025 submissions. There were votes for every whole number between 1 and 100, and 472 of the numbers between 1 and 1000. The lowest whole number that failed to pick up any votes was 110. Surely the world’s least-loved number?
Here’s the final table:

Position Number Percentage
1 7 9.7%
2 3 7.5%
3 8 6.7%
4 4 5.6%
5 5 5.1%
6 13 5.0%
7 9 4.8%
8 6 3.4%
9 2 3.4%
10 11 2.9%
11 42 2.8%
12 17 2.7%
13 23 2.3%
14 12 2.2%
15 27 1.9%
16 22 1.5%
17 21 1.4%
18 π 1.4%
19 14 1.3%
20 24 1.2%
21 1 1.2%
22 16 1.2%
23 10 1.2%
24 37 1.0%
25 0 1.0%
26 19 0.9%
27 18 0.8%
28 e 0.7%
29 28 0.7%
30 69 0.6%

Roughly speaking, we like single digits best, and the bigger a number is, the less we like it. The table also reveals a shocking indifference towards round numbers. The numbers from two to nine are all in the top ten, but ten is way down in 23rd place, twenty is in 50th and thirty in 69th. Ten is the cornerstone of the decimal system, yet it is not very lovable, possibly because it is always prostituting itself as an approximation.
Some numbers are chosen for their numerical properties, such as the phoenix number, and also the constants π and e. Usually, however, a number is chosen for a personal reason, most commonly because it is the day of the month we were born. Yet the distinction between a numerical and a personal reason is not clear-cut, since there are some numbers that are rarely chosen as favorites even if the person was born on that day. For example, if you were born on the 10th of the month, you are six times less likely to choose 10 as your favorite number than you are likely to choose 7 if you were born on the 7th of the month. If you were born on the 30th you are forty times less likely to choose 30. Some numbers evidently make better favorites than others. (One of the reasons I became so curious about favorite numbers is because I don’t have one, and I couldn’t quite believe that so many other people felt so passionately about them. Now I blame my lack of a favorite number on the fact that I was not born between the 2nd and the 9th of the month.)