diff --git a/packages/optimizely-sdk/lib/utils/fns/index.js b/packages/optimizely-sdk/lib/utils/fns/index.js
index d066c229d..78912481a 100644
--- a/packages/optimizely-sdk/lib/utils/fns/index.js
+++ b/packages/optimizely-sdk/lib/utils/fns/index.js
@@ -34,5 +34,7 @@ module.exports = {
     return uuid.v4();
   },
   values: require('lodash/values'),
-  isNumber: require('lodash/isNumber'),
+  isNumber: function(value) {
+    return typeof value === 'number';
+  },
 };
diff --git a/packages/optimizely-sdk/lib/utils/fns/index.tests.js b/packages/optimizely-sdk/lib/utils/fns/index.tests.js
index b5aaa66c8..735935794 100644
--- a/packages/optimizely-sdk/lib/utils/fns/index.tests.js
+++ b/packages/optimizely-sdk/lib/utils/fns/index.tests.js
@@ -37,5 +37,22 @@ describe('lib/utils/fns', function() {
         assert.isTrue(fns.isFinite(-Math.pow(2, 53)));
       });
     });
+    describe('isNumber', function() {
+      it('should return true in case of number', function() {
+        assert.isTrue(fns.isNumber(3));
+      });
+      it('should return true in case of value from Number object ', function() {
+        assert.isTrue(fns.isNumber(Number.MIN_VALUE));
+      });
+      it('should return true in case of Infinity ', function() {
+        assert.isTrue(fns.isNumber(Infinity));
+      });
+      it('should return false in case of string', function() {
+        assert.isFalse(fns.isNumber('3'));
+      });
+      it('should return false in case of null', function() {
+        assert.isFalse(fns.isNumber(null));
+      });
+    });
   });
 });