Complete Guide: Java Biginteger

By Harish Gowda | March 02, 2025 | 5 minutes

In this blog we will learn how to use BigInteger in Java.

Let’s get started!!!

Introduction

BigInteger allows us to work with large integers that exceed range of primitive type like int and long.

int has a max value of 2^31 -1.

long had max value of 2^63-1.

BigInteger can exceed value greater int and long.

Creating BigInteger

We can create BigInteger by specifying the value in the constructor as shown in below example.

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package examples;

import java.math.BigInteger;

public class App {

    public static void main(String[] args) {
        BigInteger bigInteger = new BigInteger("12333585357495344853");
        System.out.println(bigInteger); //12333585357495344853
    }
}

We can also create constant predefined BigInteger values of one, two and ten as shown in below examples

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package examples;

import java.math.BigInteger;

public class App {

    public static void main(String[] args) {
        BigInteger one = BigInteger.ONE;
        BigInteger two = BigInteger.TWO;
        BigInteger ten = BigInteger.TEN;
        System.out.println(one); //1
        System.out.println(two); //2
        System.out.println(ten); //10

    }
}

Arithmetic Operations

Adding 2 BigInteger numbers

We can add 2 BigInteger numbers by using add() method of the object.

It returns a BigInteger whose value is current object value + value to be added.

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package examples;

import java.math.BigInteger;

public class App {

    public static void main(String[] args) {
        BigInteger num1 = new BigInteger("12333585357495344853");
        BigInteger num2 = new BigInteger("454333585357434344999");
        System.out.println(num1.add(num2)); //466667170714929689852

    }
}

Subtracting 2 BigInteger numbers

We can subtract 2 BigInteger numbers by using subtract() method of the object.

It returns a BigInteger whose value is current object value - value to be subtracted.

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package examples;

import java.math.BigInteger;

public class App {

    public static void main(String[] args) {
        BigInteger num1 = new BigInteger("92333585357495344853");
        BigInteger num2 = new BigInteger("4543335853574343449");
        System.out.println(num1.subtract(num2)); //87790249503921001404

    }
}

Dividing 2 BigInteger numbers

We can divide 2 BigInteger numbers by using divide() method of the object.

It returns a BigInteger whose value is current object value / value to be divided.

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package examples;

import java.math.BigInteger;

public class App {

    public static void main(String[] args) {
        BigInteger num1 = new BigInteger("92333585357495344853");
        BigInteger num2 = new BigInteger("4543335853574343449");
        System.out.println(num1.divide(num2)); //20

    }
}

Multiply operation on 2 BigInteger

We can multiply 2 BigInteger numbers by using multiply() method of the object.

It returns a BigInteger whose value is current object value * value to be multiplied.

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package examples;

import java.math.BigInteger;

public class App {

    public static void main(String[] args) {
        BigInteger num1 = new BigInteger("3242342342");
        BigInteger num2 = new BigInteger("234234");
        System.out.println(num1.multiply(num2)); //759466816136028

    }
}

Advanced operations on BigIntegers

Operation like getting square root of number, raising number to the power of given exponent, getting next possible prime number can also be performed as shown in below examples.

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package examples;

import java.math.BigInteger;

public class App {

    public static void main(String[] args) {
        BigInteger num1 = new BigInteger("3242342342");
        System.out.println(num1.sqrt()); //56941
        System.out.println(num1.pow(2)); //10512783862726044964
        System.out.println(num1.nextProbablePrime()); // 3242342371

    }
}

Generating BigInteger randomly

Constructs a randomly generated BigInteger, uniformly distributed over the range 0 to (2numBits - 1).

The uniformity of the distribution assumes that a fair source of random bits is provided by random object.

It always returns non-negative BigInteger.

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package examples;

import java.math.BigInteger;
import java.util.Random;

public class App {

    public static void main(String[] args) {
        BigInteger num1 = new BigInteger(20, new Random());
        System.out.println(num1); //490906


    }
}

Generating prime numbers randomly

We can generate random prime number based on given bit length using probablePrime() method as shown in below example.

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package examples;

import java.math.BigInteger;
import java.util.Random;

public class App {

    public static void main(String[] args) {
        BigInteger prime1 = BigInteger.probablePrime(50, new Random());
        BigInteger prime2 = BigInteger.probablePrime(3, new Random());
        System.out.println(prime1); //867417845917921
        System.out.println(prime2); //5

    }
}

Comparing BigInteger using compareTo() method

We can compare 2 BigInteger numbers using compareTo() method as shown in below example.

It returns -1, 0 or 1 as this BigInteger is numerically less than, equal to, or greater than val respectively.

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package examples;

import java.math.BigInteger;

public class App {

    public static void main(String[] args) {
        BigInteger num1 = new BigInteger("3827238764238");
        BigInteger num2  = new BigInteger("34234234");
        System.out.println(num1.compareTo(num2));

    }
}

Converting BigInteger to other data types

We can convert BigInteger to data types like int,long and float as shown in below examples.

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package examples;

import java.math.BigInteger;

public class App {

    public static void main(String[] args) {
        BigInteger num1 = new BigInteger("324234");
        System.out.println(num1.intValue()); //324234
        System.out.println(num1.longValue()); //324234
        System.out.println(num1.floatValue()); // 324234.0

    }
}

BitWise operations

We can perform bitwise OR , bitwise AND and bitwise XOR operations as shown in below examples

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package examples;

import java.math.BigInteger;

public class App {

    public static void main(String[] args) {
        BigInteger num1 = new BigInteger("10");
        BigInteger num2  = new BigInteger("20");
        System.out.println(num1.or(num2)); //30
        System.out.println(num1.and(num2)); // 0
        System.out.println(num1.xor(num2)); // 30

    }
}

Conclusion

I hope this tutorial helps you to get complete understanding of BigInteger.

Thanks!!