The Elderbeast turned eleven today. And there was much rejoicing.

In age terms, eleven is a nothing number. It’s neither your entry into double figures, nor the dawn of your teens. It a transitory age in which the process of growing up tends to simply continue.

However, pop culture (thanks Stranger Things, and Spinal Tap) has bestowed great significance upon the number. And that’s not all. It’s a prime number, and the first two-digit prime number. It’s always been one of my favourite numbers mathematically, on account of being one of the easiest numbers to multiply. It also has a unique mathematical quirk … which I’m just going to paste from wikipedia:

If a number is divisible by 11, reversing its digits will result in another multiple of 11. As long as no two adjacent digits of a number added together exceed 9, then multiplying the number by 11, reversing the digits of the product, and dividing that new number by 11, will yield a number that is the reverse of the original number. (For example: 142,312 × 11 = 1,565,432 → 2,345,651 ÷ 11 = 213,241.)

There are numerous other significance to the number, including the fact that a surprising variety of sports teams utilise eleven active players.

However, my favourite is undoubtedly that eleven is the number of spacetime dimensions in M-Theory! What does that mean? I haven’t the foggiest …

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