# JavaScript data types and data structures — Number type

> The {{jsxref("Number")}} type is a double-precision 64-bit binary format IEEE 754 value.

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## Knowledge

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The {{jsxref("Number")}} type is a double-precision 64-bit binary format IEEE 754 value. It is capable of storing positive floating-point numbers between 2-1074 ({{jsxref("Number.MIN_VALUE")}}) and 21023 × (2 - 2-52) ({{jsxref("Number.MAX_VALUE")}}) as well as negative floating-point numbers of the same magnitude, but it can only safely store integers in the range -(253 − 1) ({{jsxref("Number.MIN_SAFE_INTEGER")}}) to 253 − 1 ({{jsxref("Number.MAX_SAFE_INTEGER")}}). Outside this range, JavaScript can no longer safely represent integers; they will instead be represented by a double-precision floating point approximation. You can check if a number is within the range of safe integers using {{jsxref("Number.isSafeInteger()")}}.

Values outside the representable range are automatically converted

Positive values greater than {{jsxref("Number.MAX_VALUE")}} are converted to Infinity. Positive values smaller than {{jsxref("Number.MIN_VALUE")}} are converted to 0. Negative values smaller than -{{jsxref("Number.MAX_VALUE")}} are converted to -Infinity. Negative values greater than -{{jsxref("Number.MIN_VALUE")}} are converted to -0.

Infinity and -Infinity behave similarly to mathematical infinity, but with some slight differences; see {{jsxref("Number.POSITIVE_INFINITY")}} and {{jsxref("Number.NEGATIVE_INFINITY")}} for details.

The Number type has only one value with multiple representations: 0 is represented as both -0 and +0 (where 0 is an alias for +0). In practice, there is almost no difference between the different representations; for example, +0 === -0 is true. However, you are able to notice this when you divide by zero

{{jsxref("NaN")}} ("Not a Number") is a special kind of number value that's typically encountered when the result of an arithmetic operation cannot be expressed as a number. It is also the only value in JavaScript that is not equal to itself.

Although a number is conceptually a "mathematical value" and is always implicitly floating-point-encoded, JavaScript provides bitwise operators. When applying bitwise operators, the number is first converted to a 32-bit integer. …

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