The Number.MAX_SAFE_INTEGER static data property represents the maximum safe integer in JavaScript (253 – 1).
For larger integers, consider using BigInt.
Value
9007199254740991 (9,007,199,254,740,991, or \~9 quadrillion).
Description
Double precision floating point format only has 52 bits to represent the mantissa, so it can only safely represent integers between -(253 – 1) and 253 – 1. "Safe" in this context refers to the ability to represent integers exactly and to compare them correctly. For example, Number.MAX_SAFE_INTEGER + 1 === Number.MAX_SAFE_INTEGER + 2 will evaluate to true, which is mathematically incorrect. See Number.isSafeInteger for more information.
Because MAX_SAFE_INTEGER is a static property of Number, you always use it as Number.MAX_SAFE_INTEGER, rather than as a property of a number value.
Examples
Return value of MAX_SAFE_INTEGER
Number.MAX_SAFE_INTEGER; // 9007199254740991
Relationship between MAX_SAFE_INTEGER and EPSILON
Number.EPSILON is 2-52, while MAX_SAFE_INTEGER is 253 – 1 — both of them are derived from the width of the mantissa, which is 53 bits (with the highest bit always being 1). Multiplying them will give a value very close — but not equal — to 2.
Number.MAX_SAFE_INTEGER * Number.EPSILON; // 1.9999999999999998