Create findsumofalldivisorsofn.java

findsumofalldivisorsofn.java

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+// Formula based Java program to
+import java.util.*;
+import java.lang.*;
+
+public class GfG {
+
+	// Returns sum of all factors of n.
+	public static int sumofFactors(int n)
+	{
+		// If n is odd, then there
+		// are no even factors.
+		if (n % 2 != 0)
+			return 0;
+
+		// Traversing through all prime
+		// factors.
+		int res = 1;
+		for (int i = 2; i <= Math.sqrt(n); i++) {
+			int count = 0, curr_sum = 1;
+			int curr_term = 1;
+
+			// While i divides n, print i and
+			// divide n
+			while (n % i == 0) {
+				count++;
+
+				n = n / i;
+
+				// here we remove the 2^0 that
+				// is 1. All other factors
+				if (i == 2 && count == 1)
+					curr_sum = 0;
+
+				curr_term *= i;
+				curr_sum += curr_term;
+			}
+
+			res *= curr_sum;
+		}
+
+		// This condition is to handle the
+		// case when n is a prime number.
+		if (n >= 2)
+			res *= (1 + n);
+
+		return res;
+	}
+
+	// Driver function
+	public static void main(String argc[])
+	{
+		int n = 18;
+		System.out.println(sumofFactors(n));
+	}
+}
+
+/* This code is contributed by Sagar Shukla */