Prime Numbers

Prime numbers are one of the fundamental areas of mathematics, and we all need to know about them. Most likely similar to a lot of you, I simply didn’t care about primes. That was until I watched the Ted Talk ‘Monster Primes’ by Adam Spencer, a mathematician who seems more suited to the role of a comedian, or ‘mathecomedian’ as I sometimes like to call it. In the video, he discusses not only many of the largest primes, he discusses how to find them, and some of the history behind the search for monster primes.

Click Here to watch ‘Monster Primes’

A prime number means a number that only has two factors, one and itself. This may be all you’ve ever learnt, but there is far more to it than that, especially when it comes to finding primes in the first place. In the ted talk, Adam Spencer explains that a large prime can be found by taking 2 to the power of a prime, and subtracting one, resulting in and even larger one. However, there are many exceptions. While 2¹³ – 1 = 8191, which is prime, 2¹¹ – 1 = 2047, which is 23 x 89. The current largest known prime is 2^74,207,281 – 1, with a total of 22,338,618 digits. But how on Earth do they know that it really is prime? Although it is a long, time consuming process, the shortest method available is known as trial division. This is the process of dividing the number in question (n) by every number between 2 and n. Unless every single one is not whole, the number is composite. Suggestions for future posts? Put them down in the comments below.

Yours in numbers,

Lachlan

This prime number calculator is from https://en.wikipedia.org/wiki/Prime_number.

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