diff --git a/math/lcm_sum.cpp b/math/lcm_sum.cpp
index 60bac3283..dd9667b49 100644
--- a/math/lcm_sum.cpp
+++ b/math/lcm_sum.cpp
@@ -1,13 +1,13 @@
 /**
  * @file
- * @brief An algorithm to calculate the sum of LCM: \f$\mathrm{LCM}(1,n) + \mathrm{LCM}(2,n) + \ldots + \mathrm{LCM}(n,n)\f$
+ * @brief An algorithm to calculate the sum of LCM: \f$\mathrm{LCM}(1,n) + \mathrm{LCM}(2,n) + .. + \mathrm{LCM}(n,n)\f$
  * @details An algorithm to calculate the sum of LCM: \f$\mathrm{LCM}(1,n) + \mathrm{LCM}(2,n) + .. + \mathrm{LCM}(n,n)\f$ where \f$\mathrm{LCM}(i,n)\f$
  * denotes the Least Common Multiple of the integers i and n. For n greater than or equal to 1.
  * The value of the sum is calculated by formula:
  * \f[
  * \sum\mathrm{LCM}(i, n) = \frac{1}{2} \left[\left(\sum (d * \mathrm{ETF}(d)) + 1\right) * n\right]
  * \f]
- *
+ * where \mathrm{ETF}(i) represents Euler totient function of i.
  * @author [Chesta Mittal](https://github.com/chestamittal)
  */
 
@@ -25,11 +25,11 @@ namespace math {
      * @param num input number
      * @returns int Sum of LCMs, i.e. ∑LCM(i, num) from i = 1 to num
      */
-    int lcmSum(int num) {
+    uint64_t lcmSum(uint64_t num) {
    
-        int i=0, j=0;
-        std::vector <int> eulerTotient(num+1);
-        std::vector <int> sumOfEulerTotient(num+1);
+        uint64_t i=0, j=0;
+        std::vector <uint64_t> eulerTotient(num+1);
+        std::vector <uint64_t> sumOfEulerTotient(num+1);
    
         // storing initial values in eulerTotient vector
         for(i=1; i<=num; i++) {
@@ -63,28 +63,28 @@ namespace math {
  * @returns `void`
 */
 static void test() {
-    int n = 2;
-    int test_1 = math::lcmSum(n);
+    uint64_t n = 2;
+    uint64_t test_1 = math::lcmSum(n);
     assert(test_1 == 4);
     std::cout << "Passed Test 1!" << std::endl;
 
     n = 5;
-    int test_2 = math::lcmSum(n);
+    uint64_t test_2 = math::lcmSum(n);
     assert(test_2 == 55);
     std::cout << "Passed Test 2!" << std::endl;
 
     n = 10;
-    int test_3 = math::lcmSum(n);
+    uint64_t test_3 = math::lcmSum(n);
     assert(test_3 == 320);
     std::cout << "Passed Test 3!" << std::endl;
 
     n = 11;
-    int test_4 = math::lcmSum(n);
+    uint64_t test_4 = math::lcmSum(n);
     assert(test_4 == 616);
     std::cout << "Passed Test 4!" << std::endl;
 
     n = 15;
-    int test_5 = math::lcmSum(n);
+    uint64_t test_5 = math::lcmSum(n);
     assert(test_5 == 1110);
     std::cout << "Passed Test 5!" << std::endl;
 }