Large numbers erroneously rounded in JavaScript

Answer 1

JavaScript uses double precision floating point values, ie a total precision of 53 bits, but you need

ceil(lb 714341252076979033) = 60

bits to exactly represent the value.

The nearest exactly representable number is 714341252076979072 (write the original number in binary, replace the last 7 digits with 0 and round up because the highest replaced digit was 1).

You'll get 714341252076979100 instead of this number because ToString() as described by ECMA-262, §9.8.1 works with powers of ten and in 53 bit precision all these numbers are equal.