This is super weird. How did you discover this?

I discovered it based on replies on this tweet https://twitter.com/dbumbeishvili/status/1288815981683507201

Looks like it might be related to this: https://www.ecma-international.org/ecma-262/10.0/index.html#sec-ecmascript-language-types-string-type > The String type is the set of all ordered sequences of zero or more 16-bit unsigned integer values (“elements”) up to a maximum length of 253 - 1 elements.

@aaronkyle No, that refers to UTF-16. The above is a number, not a string.

Ah! My mistake! Was just trying to figure out why this is happening!

This is 2**53+1. Double-precision floating point only stores 53 bits of mantissa.