diff --git a/big.js b/big.js
index 7743ddd..fb55576 100644
--- a/big.js
+++ b/big.js
@@ -111,7 +111,16 @@
 
       // Retain a reference to this Big constructor.
       // Shadow Big.prototype.constructor which points to Object.
-      x.constructor = Big;
+      if (typeof Object.defineProperty === 'function') {
+        // If the Object prototype is frozen, the "constructor" property is non-writable. This means that any objects which inherit this
+        // property cannot have the property changed using an assignment. If using strict mode, attempting that will cause an error. If not
+        // using strict mode, attempting that will be silently ignored.
+        // However, we can still explicitly shadow the prototype's non-writable property by defining a new property on this object.
+        Object.defineProperty(x, 'constructor', { value: Big });
+      } else {
+        // If Object.defineProperty() doesn't exist, attempt to shadow this property using the assignment operator.
+        x.constructor = Big;
+      }
     }
 
     Big.prototype = P;
@@ -960,7 +969,7 @@
    * Big.PE, or a negative exponent equal to or less than Big.NE.
    * Omit the sign for negative zero.
    */
-  P.toJSON = P.toString = function () {
+  function toString() {
     var x = this,
       Big = x.constructor;
     return stringify(x, x.e <= Big.NE || x.e >= Big.PE, !!x.c[0]);
@@ -1011,7 +1020,7 @@
    * Big.PE, or a negative exponent equal to or less than Big.NE.
    * Include the sign for negative zero.
    */
-  P.valueOf = function () {
+  function valueOf() {
     var x = this,
       Big = x.constructor;
     if (Big.strict === true) {
@@ -1021,6 +1030,21 @@
   };
 
 
+  P.toJSON = toString;
+  if (typeof Object.defineProperty === 'function') {
+    // If the Object prototype is frozen, the "toString" and "valueOf" properties are non-writable. This means that any objects which
+    // inherit these property cannot have the property changed using an assignment. If using strict mode, attempting that will cause an
+    // error. If not using strict mode, attempting that will be silently ignored.
+    // However, we can still explicitly shadow the prototype's non-writable properties by defining new properties on this object.
+    Object.defineProperty(P, 'toString', { value: toString });
+    Object.defineProperty(P, 'valueOf', { value: valueOf });
+  } else {
+    // If Object.defineProperty() doesn't exist, attempt to shadow this property using the assignment operator.
+    P.toString = toString;
+    P.valueOf = valueOf;
+  }
+
+
   // Export
 
 
diff --git a/big.mjs b/big.mjs
index 079b743..5932c2c 100644
--- a/big.mjs
+++ b/big.mjs
@@ -108,7 +108,11 @@ function _Big_() {
 
     // Retain a reference to this Big constructor.
     // Shadow Big.prototype.constructor which points to Object.
-    x.constructor = Big;
+    // If the Object prototype is frozen, the "constructor" property is non-writable. This means that any objects which inherit this
+    // property cannot have the property changed using an assignment. If using strict mode, attempting that will cause an error. If not
+    // using strict mode, attempting that will be silently ignored.
+    // However, we can still explicitly shadow the prototype's non-writable property by defining a new property on this object.
+    Object.defineProperty(x, 'constructor', { value: Big });
   }
 
   Big.prototype = P;
@@ -957,7 +961,7 @@ P.toFixed = function (dp, rm) {
  * Big.PE, or a negative exponent equal to or less than Big.NE.
  * Omit the sign for negative zero.
  */
-P[Symbol.for('nodejs.util.inspect.custom')] = P.toJSON = P.toString = function () {
+var toString = P[Symbol.for('nodejs.util.inspect.custom')] = function () {
   var x = this,
     Big = x.constructor;
   return stringify(x, x.e <= Big.NE || x.e >= Big.PE, !!x.c[0]);
@@ -1008,7 +1012,7 @@ P.toPrecision = function (sd, rm) {
  * Big.PE, or a negative exponent equal to or less than Big.NE.
  * Include the sign for negative zero.
  */
-P.valueOf = function () {
+function valueOf() {
   var x = this,
     Big = x.constructor;
   if (Big.strict === true) {
@@ -1018,6 +1022,15 @@ P.valueOf = function () {
 };
 
 
+P.toJSON = toString;
+// If the Object prototype is frozen, the "toString" and "valueOf" properties are non-writable. This means that any objects which
+// inherit these property cannot have the property changed using an assignment. If using strict mode, attempting that will cause an
+// error. If not using strict mode, attempting that will be silently ignored.
+// However, we can still explicitly shadow the prototype's non-writable properties by defining new properties on this object.
+Object.defineProperty(P, 'toString', { value: toString });
+Object.defineProperty(P, 'valueOf', { value: valueOf });
+
+
 // Export