The value of the MAX SAFE INTEGER constant is 9007199254740991 (9,007,199,254,740,991 or nine quadrillion). JavaScript only properly represents integers between -(253 - 1) and 253 - 1, which is the rationale for that number. JavaScript employs double-precision floating-point format numbers as specified in IEEE 754. Number and BigInt are the two number types available in JavaScript. Number, the most popular type of number, is a 64-bit floating point IEEE 754 number.