diff --git a/src/rpc/mining.cpp b/src/rpc/mining.cpp
--- a/src/rpc/mining.cpp
+++ b/src/rpc/mining.cpp
@@ -30,6 +30,7 @@
 #include <txmempool.h>
 #include <univalue.h>
 #include <util/strencodings.h>
+#include <util/string.h>
 #include <util/system.h>
 #include <validation.h>
 #include <validationinterface.h>
@@ -984,7 +985,7 @@
     result.pushKV("coinbasetxn", coinbasetxn);
     result.pushKV("coinbasevalue", int64_t(coinbasevalue / SATOSHI));
     result.pushKV("longpollid", ::ChainActive().Tip()->GetBlockHash().GetHex() +
-                                    i64tostr(nTransactionsUpdatedLast));
+                                    ToString(nTransactionsUpdatedLast));
     result.pushKV("target", hashTarget.GetHex());
     result.pushKV("mintime", int64_t(pindexPrev->GetMedianTimePast()) + 1);
     result.pushKV("mutable", aMutable);
diff --git a/src/test/fuzz/integer.cpp b/src/test/fuzz/integer.cpp
--- a/src/test/fuzz/integer.cpp
+++ b/src/test/fuzz/integer.cpp
@@ -26,6 +26,7 @@
 #include <uint256.h>
 #include <util/moneystr.h>
 #include <util/strencodings.h>
+#include <util/string.h>
 #include <util/system.h>
 #include <util/time.h>
 #include <version.h>
@@ -91,7 +92,7 @@
     // ()GetVirtualTransactionSize(i64, i64, u32);
     (void)HexDigit(ch);
     (void)MoneyRange(i64 * SATOSHI);
-    (void)i64tostr(i64);
+    (void)ToString(i64);
     (void)IsDigit(ch);
     (void)IsSpace(ch);
     (void)IsSwitchChar(ch);
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
@@ -3,6 +3,7 @@
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <util/strencodings.h>
+#include <util/string.h>
 
 #include <test/fuzz/FuzzedDataProvider.h>
 #include <test/fuzz/fuzz.h>
@@ -805,7 +806,7 @@
     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 i64tostr_without_locale = i64tostr(random_int64);
+    const std::string tostring_without_locale = ToString(random_int64);
     const int32_t random_int32 =
         fuzzed_data_provider.ConsumeIntegral<int32_t>();
     const std::string strprintf_int_without_locale =
@@ -838,8 +839,8 @@
     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 i64tostr_with_locale = i64tostr(random_int64);
-    assert(i64tostr_without_locale == i64tostr_with_locale);
+    const std::string tostring_with_locale = ToString(random_int64);
+    assert(tostring_without_locale == tostring_with_locale);
     const std::string strprintf_int_with_locale = strprintf("%d", random_int64);
     assert(strprintf_int_without_locale == strprintf_int_with_locale);
     const std::string strprintf_double_with_locale =
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);
-std::string i64tostr(int64_t n);
 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
@@ -451,10 +451,6 @@
     return out.str();
 }
 
-std::string i64tostr(int64_t n) {
-    return strprintf("%d", n);
-}
-
 int64_t atoi64(const char *psz) {
 #ifdef _MSC_VER
     return _atoi64(psz);
diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -16,6 +16,7 @@
 #include <tinyformat.h>
 #include <util/message.h>
 #include <util/strencodings.h>
+#include <util/string.h>
 #include <util/system.h>
 #include <util/translation.h>
 #include <util/ui_change_type.h>
@@ -239,7 +240,7 @@
     if (nOrderPos == -1) {
         return;
     }
-    mapValue["n"] = i64tostr(nOrderPos);
+    mapValue["n"] = ToString(nOrderPos);
 }
 
 struct COutputEntry {