diff --git a/src/test/fuzz/locale.cpp b/src/test/fuzz/locale.cpp
--- a/src/test/fuzz/locale.cpp
+++ b/src/test/fuzz/locale.cpp
@@ -803,7 +803,6 @@
         ParseInt64(random_string, &parseint64_out_without_locale);
     const int64_t atoi64_without_locale = atoi64(random_string);
     const int atoi_without_locale = atoi(random_string);
-    const int64_t atoi64c_without_locale = atoi64(random_string.c_str());
     const int64_t random_int64 =
         fuzzed_data_provider.ConsumeIntegral<int64_t>();
     const std::string tostring_without_locale = ToString(random_int64);
@@ -839,8 +838,6 @@
     }
     const int64_t atoi64_with_locale = atoi64(random_string);
     assert(atoi64_without_locale == atoi64_with_locale);
-    const int64_t atoi64c_with_locale = atoi64(random_string.c_str());
-    assert(atoi64c_without_locale == atoi64c_with_locale);
     const int atoi_with_locale = atoi(random_string);
     assert(atoi_without_locale == atoi_with_locale);
     const std::string tostring_with_locale = ToString(random_int64);
diff --git a/src/util/strencodings.h b/src/util/strencodings.h
--- a/src/util/strencodings.h
+++ b/src/util/strencodings.h
@@ -62,7 +62,6 @@
 std::string EncodeBase32(const std::string &str);
 
 void SplitHostPort(std::string in, int &portOut, std::string &hostOut);
-int64_t atoi64(const char *psz);
 int64_t atoi64(const std::string &str);
 int atoi(const std::string &str);
 
diff --git a/src/util/strencodings.cpp b/src/util/strencodings.cpp
--- a/src/util/strencodings.cpp
+++ b/src/util/strencodings.cpp
@@ -451,14 +451,6 @@
     return out.str();
 }
 
-int64_t atoi64(const char *psz) {
-#ifdef _MSC_VER
-    return _atoi64(psz);
-#else
-    return strtoll(psz, nullptr, 10);
-#endif
-}
-
 int64_t atoi64(const std::string &str) {
 #ifdef _MSC_VER
     return _atoi64(str.c_str());
diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -232,7 +232,7 @@
         return;
     }
 
-    nOrderPos = atoi64(mapValue["n"].c_str());
+    nOrderPos = atoi64(mapValue["n"]);
 }
 
 static inline void WriteOrderPos(const int64_t &nOrderPos,