diff --git a/math/mathcore/src/MixMaxEngineImpl.h b/math/mathcore/src/MixMaxEngineImpl.h
index 1f50baf224cc73c94b697ada9de1851b7dadfd80..4dedd701b9bc61bc828e3ffc42d89c92a1bbaf8a 100644
--- a/math/mathcore/src/MixMaxEngineImpl.h
+++ b/math/mathcore/src/MixMaxEngineImpl.h
@@ -8,11 +8,11 @@
 #define ROOT_Math_MixMaxEngineImpl
 
 
-#if (_NN==17)
+#if (ROOT_MM_N==17)
 namespace mixmax_17 {
-#elif (_NN==240)
+#elif (ROOT_MM_N==240)
 namespace mixmax_240 {
-#elif (_NN==256)
+#elif (ROOT_MM_N==256)
 namespace mixmax_256 {
 #else
 namespace { 
@@ -31,11 +31,11 @@ namespace {
 
 #include <iostream>
 
-#if (_NN==17)
+#if (ROOT_MM_N==17)
 using namespace mixmax_17;
-#elif (_NN==240)
+#elif (ROOT_MM_N==240)
 using namespace mixmax_240;
-#elif (_NN==256)
+#elif (ROOT_MM_N==256)
 using namespace mixmax_256;
 #endif
 
@@ -65,12 +65,12 @@ namespace ROOT {
 
 
 template<> 
-class MixMaxEngineImpl<_NN> {
+class MixMaxEngineImpl<ROOT_MM_N> {
    rng_state_t * fRngState;
 public:
 
-   typedef MixMaxEngine<_NN,0>::StateInt_t StateInt_t; 
-   typedef MixMaxEngine<_NN,0>::Result_t Result_t;
+   typedef MixMaxEngine<ROOT_MM_N,0>::StateInt_t StateInt_t; 
+   typedef MixMaxEngine<ROOT_MM_N,0>::Result_t Result_t;
    
    MixMaxEngineImpl(uint64_t seed) {
       fRngState = rng_alloc();
diff --git a/math/mathcore/src/MixMaxEngineImpl17.cxx b/math/mathcore/src/MixMaxEngineImpl17.cxx
index 93ec90007530ae8a3fa6eabf87bffba53af3d12b..39ed0852a5d21f1e6f9636f9ec5fcf46fed19478 100644
--- a/math/mathcore/src/MixMaxEngineImpl17.cxx
+++ b/math/mathcore/src/MixMaxEngineImpl17.cxx
@@ -1,7 +1,7 @@
 
 
 // define number for used to Mixmax
-#define _NN 17
+#define ROOT_MM_N 17
 
 #include "MixMaxEngineImpl.h"
 
diff --git a/math/mathcore/src/MixMaxEngineImpl240.cxx b/math/mathcore/src/MixMaxEngineImpl240.cxx
index 5aa4c8b27881b24cb5bdb19a8ff8a6927f47f9e3..ff0f865052fc90496024a667cc7e67daa8f2951a 100644
--- a/math/mathcore/src/MixMaxEngineImpl240.cxx
+++ b/math/mathcore/src/MixMaxEngineImpl240.cxx
@@ -1,7 +1,7 @@
 
 
 // define number for used to Mixmax
-#define _NN 240
+#define ROOT_MM_N 240
 
 #include "MixMaxEngineImpl.h"
 
diff --git a/math/mathcore/src/MixMaxEngineImpl256.cxx b/math/mathcore/src/MixMaxEngineImpl256.cxx
index fa1d67adc1de95099b260fb820938fdfeafa4dc0..e437126678a3aa3d4f41698e75d59d4cba7b0c4e 100644
--- a/math/mathcore/src/MixMaxEngineImpl256.cxx
+++ b/math/mathcore/src/MixMaxEngineImpl256.cxx
@@ -1,7 +1,7 @@
 
 
 // define number for used to Mixmax
-#define _NN 256
+#define ROOT_MM_N 256
 
 #include "MixMaxEngineImpl.h"
 
diff --git a/math/mathcore/src/mixmax.h b/math/mathcore/src/mixmax.h
index 5a26c7b1ddd28fbce45bb5b1d338fd2757597c9f..80a3a4690c2130e2a92316a9f8f0ac22ab2cc5a1 100644
--- a/math/mathcore/src/mixmax.h
+++ b/math/mathcore/src/mixmax.h
@@ -27,7 +27,7 @@
 //extern "C" {
 //#endif
 
-#ifndef _NN
+#ifndef ROOT_MM_N
 #define N 240
 /* The currently recommended generator is the three-parameter MIXMAX with
 N=240, s=487013230256099140, m=2^51+1
@@ -38,7 +38,7 @@ N=240, s=487013230256099140, m=2^51+1
    Since the algorithm is linear in N, the cost per number is almost independent of N.
  */
 #else
-#define N _NN
+#define N ROOT_MM_N
 #endif
 
 #ifndef __LP64__