The java.math.BigInteger.modInverse(BigInteger m) returns a BigInteger whose value is (this-1 mod m). Using this method you can calculate Modular multiplicative inverse for a given number.ProgramLive Demoimport java.math.*; public class BigIntegerDemo {    public static void main(String[] args) {       // create 3 BigInteger objects       BigInteger bi1, bi2, bi3;             // create a BigInteger exponent       BigInteger exponent = new BigInteger("2");       bi1 = new BigInteger("7");       bi2 = new BigInteger("20");             // perform modPow operation on bi1 using bi2 and exp       bi3 = bi1.modPow(exponent, bi2);       String str = bi1 + "^" +exponent+ " mod " + bi2 + " is " +bi3;             // print bi3 value       System.out.println( str );    } }Output7^2 mod 20 is 9

The java.math.BigInteger.modPow(BigInteger exponent, BigInteger m) returns a BigInteger whose value is (thisexponent mod m). Unlike pow, this method permits negative exponents. You can calculate the modular Exponentiation using this method.ProgramLive Demoimport java.math.*; public class BigIntegerDemo {    public static void main(String[] args) {       // create 3 BigInteger objects       BigInteger bi1, bi2, bi3;             // create a BigInteger exponent       BigInteger exponent = new BigInteger("2");       bi1 = new BigInteger("7");       bi2 = new BigInteger("20");             // perform ... Read More