Java Data Type - 如何否定/乘/减一个BigInteger到另一个BigInteger

import java.math.BigInteger;

public class Main {
  public static void main(String[] argv) throws Exception {
    BigInteger bi1 = new BigInteger("1234567890123456890");
    BigInteger bi2 = BigInteger.valueOf(123L);

    bi1 = bi1.multiply(bi2);

    bi1 = bi1.subtract(bi2);

    bi1 = bi1.divide(bi2);

    bi1 = bi1.negate();

  }
}