Number.parseInt(string, radix)

• Converts a string into an integer.

console.log(Number.parseInt("42")); // 42

Number.parseFloat(string)

• Converts a string into a floating-point number.

console.log(Number.parseFloat("3.14")); // 3.14

Number.isInteger(value)

• Checks if a value is an integer.

console.log(Number.isInteger(10));   // true
console.log(Number.isInteger(10.5)); // false

Number.isNaN(value)

• Checks if a value is NaN.

console.log(Number.isNaN(NaN));   // true
console.log(Number.isNaN(10 / "a")); // true
console.log(Number.isNaN("hello")); // false

Number.toFixed(digits)

• Formats a number to a fixed number of decimal places.

let num = 3.14159;
console.log(num.toFixed(2)); // "3.14"

Number.toPrecision(digits)

• Formats a number to a specified precision.

console.log((123.456).toPrecision(4)); // "123.5"