The Most Random Number

Think of a number from one to 100. Is it 37? I knew it. You may think my guess was completely coincidental, but in reality, it was not. In fact, 37 is the most useful, most random, and objectively best number. In this article, I will explain why 37 is so random and why it is my favorite number.

First of all, humans are notoriously bad at choosing random numbers. When choosing a number 1 through 100, it’s a known fact that we reliably select the number 37. This is similar to the “blue 7” effect, where the color blue and the number 7 dominate choices in color and number selection across cultures. Also, among numbers from 1 through 10, 3 and 7 are the most chosen primes, mainly because 2 and 5 don’t seem too random. The preference for 37 is similar; it arises from its oddity and lack of factors, which gives a sense of distinctness from other numbers. People veer away from the extremes, like one and 100, and obvious patterns, like multiples of 10. Additionally, odd numbers feel less structured than even numbers, and primes make them more random because of their indivisibility. Among primes, 37’s combination of not being too complex and its perceived randomness gives it a special appeal.

Culturally, 37 has taken other forms of importance, from magic tricks to hacker slang. A professional magic trick called the “37-Force” relies on the predictable tendency of people to choose 37 when asked for a random number. Similarly, the number 37 appears in the Stanford-MIT Jargon File as a default choice for randomness among programmers.

Mathematically, 37 has many remarkable properties. First, it’s a prime number, which automatically makes it interesting. More fascinatingly, 37 is the median second prime factor of all integers. Okay, let's take a step back, and understand what this means. What is a second prime factor? The number 5 is the second prime factor of 15 because 15’s prime factors are 3 and 5. Amazingly, the median second prime factor for all numbers is 37. Here’s why: Three is the second prime factor when a number is divisible by two and three, or divisible by six. This means that one-sixth of numbers have three as their second prime factor. If you continue to count the second prime factors of all numbers, 37 becomes the prime factor that crosses the one-half mark, meaning that 37 is the median second prime factor of all numbers! Put another way, the majority of numbers have a second prime factor of less than or equal to… 37!

Lastly, 37 plays a pivotal role in decision-making strategies.  The 37 percent rule says that people should reject the first 37% of all options in order to gather information, and then select the next best option (better than the best option from the first 37%). This principle applies to almost all problems that involve sequential decision-making.

In conclusion, 37 has many important roles in everyday life, from being the most random number to assisting people in decision-making.