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BigInteger longValue() Method in Java
• Last Updated : 04 Dec, 2018

The java.math.BigInteger.longValue() converts this BigInteger to a long value. If the value return by this function is too big to fit into long value, then it will return only the low-order 64 bits. There is chance that this conversion can loose information about the overall magnitude of the BigInteger value. This method can also return the result with opposite sign.

Syntax:

`public long longValue()`

Returns: The method returns a long value which represents long value for this BigInteger.

Examples:

```Input: BigInteger1=3214558191
Output: 3214558191
Explanation: BigInteger1.longValue()=3214558191.

Input: BigInteger1=32145535361361525377
Output: -4747952786057577855
Explanation: BigInteger1.longValue()=-4747952786057577855. This BigInteger is too big for
longValue so it is returning lower 64 bit.
```

Example 1: Below programs illustrate longValue() method of BigInteger class

 `// Java program to demonstrate longValue() method of BigInteger`` ` `import` `java.math.BigInteger;`` ` `public` `class` `GFG {`` ` `    ``public` `static` `void` `main(String[] args)``    ``{`` ` `        ``// Creating 2 BigInteger objects``        ``BigInteger b1, b2;`` ` `        ``b1 = ``new` `BigInteger(``"3214553537"``);``        ``b2 = ``new` `BigInteger(``"76137217351"``);`` ` `        ``// apply longValue() method``        ``long` `longValueOfb1 = b1.longValue();``        ``long` `longValueOfb2 = b2.longValue();`` ` `        ``// print longValue``        ``System.out.println(``"longValue of "``                           ``+ b1 + ``" : "` `+ longValueOfb1);``        ``System.out.println(``"longValue of "``                           ``+ b2 + ``" : "` `+ longValueOfb2);``    ``}``}`
Output:
```longValue of 3214553537 : 3214553537
longValue of 76137217351 : 76137217351
```

Example 2: when return long is too big for long value.

 `// Java program to demonstrate longValue() method of BigInteger`` ` `import` `java.math.BigInteger;`` ` `public` `class` `GFG {`` ` `    ``public` `static` `void` `main(String[] args)``    ``{``        ``// Creating 2 BigInteger objects``        ``BigInteger b1, b2;`` ` `        ``b1 = ``new` `BigInteger(``"32145535361361525377"``);``        ``b2 = ``new` `BigInteger(``"7613721535372632367351"``);`` ` `        ``// apply longValue() method``        ``long` `longValueOfb1 = b1.longValue();``        ``long` `longValueOfb2 = b2.longValue();`` ` `        ``// print longValue``        ``System.out.println(``"longValue of "``                           ``+ b1 + ``" : "` `+ longValueOfb1);``        ``System.out.println(``"longValue of "``                           ``+ b2 + ``" : "` `+ longValueOfb2);``    ``}``}`
Output:
```longValue of 32145535361361525377 : -4747952786057577855
longValue of 7613721535372632367351 : -4783767069412450057
```

Reference:
BigInteger longValue() Docs

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