diff --git a/src/GRANULAR/fix_pour.cpp b/src/GRANULAR/fix_pour.cpp
index 9ecde81f53..54b7366003 100644
--- a/src/GRANULAR/fix_pour.cpp
+++ b/src/GRANULAR/fix_pour.cpp
@@ -263,7 +263,7 @@ FixPour::FixPour(LAMMPS *lmp, int narg, char **arg) :
 
   nper = static_cast<int> (volfrac*volume/volume_one);
   if (nper == 0) error->all(FLERR,"Fix pour insertion count per timestep is 0");
-  int nfinal = update->ntimestep + 1 + (ninsert-1)/nper * nfreq;
+  int nfinal = update->ntimestep + 1 + ((bigint)ninsert-1)/nper * nfreq;
 
   // print stats
 
@@ -705,10 +705,10 @@ void FixPour::pre_exchange()
     if (atom->natoms < 0)
       error->all(FLERR,"Too many total atoms");
     if (mode == MOLECULE) {
-      atom->nbonds += onemols[imol]->nbonds * ninserted_mols;
-      atom->nangles += onemols[imol]->nangles * ninserted_mols;
-      atom->ndihedrals += onemols[imol]->ndihedrals * ninserted_mols;
-      atom->nimpropers += onemols[imol]->nimpropers * ninserted_mols;
+      atom->nbonds += (bigint)onemols[imol]->nbonds * ninserted_mols;
+      atom->nangles += (bigint)onemols[imol]->nangles * ninserted_mols;
+      atom->ndihedrals += (bigint)onemols[imol]->ndihedrals * ninserted_mols;
+      atom->nimpropers += (bigint)onemols[imol]->nimpropers * ninserted_mols;
     }
     if (maxtag_all >= MAXTAGINT)
       error->all(FLERR,"New atom IDs exceed maximum allowed ID");
diff --git a/src/REPLICA/prd.cpp b/src/REPLICA/prd.cpp
index bd9525ea10..de45116194 100644
--- a/src/REPLICA/prd.cpp
+++ b/src/REPLICA/prd.cpp
@@ -310,7 +310,7 @@ void PRD::command(int narg, char **arg)
       dynamics(t_event,time_dynamics);
       fix_event->store_state_quench();
       quench();
-      clock = clock + t_event*universe->nworlds;
+      clock += (bigint)t_event*universe->nworlds;
       ireplica = check_event();
       if (ireplica >= 0) break;
       fix_event->restore_state_quench();
diff --git a/src/USER-DIFFRACTION/fix_saed_vtk.cpp b/src/USER-DIFFRACTION/fix_saed_vtk.cpp
index 26bc4dc0a1..90eedb1127 100644
--- a/src/USER-DIFFRACTION/fix_saed_vtk.cpp
+++ b/src/USER-DIFFRACTION/fix_saed_vtk.cpp
@@ -343,7 +343,7 @@ void FixSAEDVTK::invoke_vector(bigint ntimestep)
   }
 
   irepeat = 0;
-  nvalid = ntimestep+nfreq - (nrepeat-1)*nevery;
+  nvalid = ntimestep+nfreq - ((bigint)nrepeat-1)*nevery;
   modify->addstep_compute(nvalid);
 
   // average the final result for the Nfreq timestep
@@ -554,7 +554,7 @@ bigint FixSAEDVTK::nextvalid()
   if (nvalid-nfreq == update->ntimestep && nrepeat == 1)
     nvalid = update->ntimestep;
   else
-    nvalid -= (nrepeat-1)*nevery;
+    nvalid -= ((bigint)nrepeat-1)*nevery;
   if (nvalid < update->ntimestep) nvalid += nfreq;
   return nvalid;
 }
diff --git a/src/USER-OMP/reaxc_forces_omp.cpp b/src/USER-OMP/reaxc_forces_omp.cpp
index 7fe6a41e9d..5eb939cf8c 100644
--- a/src/USER-OMP/reaxc_forces_omp.cpp
+++ b/src/USER-OMP/reaxc_forces_omp.cpp
@@ -145,7 +145,7 @@ void Compute_Total_ForceOMP( reax_system *system, control_params *control,
 
   int natoms = system->N;
   int nthreads = control->nthreads;
-  long totalReductionSize = system->N * nthreads;
+  long totalReductionSize = (bigint)system->N * nthreads;
   reax_list *bonds = (*lists) + BONDS;
 
 #if defined(_OPENMP)
@@ -381,8 +381,8 @@ void Init_Forces_noQEq_OMP( reax_system *system, control_params *control,
 #else
     int tid = 0;
 #endif
-    long reductionOffset = system->N * tid;
-    long totalReductionSize = system->N * nthreads;
+    long reductionOffset = (bigint)system->N * tid;
+    long totalReductionSize = (bigint)system->N * nthreads;
 
 #if defined(_OPENMP)
 #pragma omp for schedule(dynamic,50) reduction(+:num_bonds)