diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 5f3807ec889..3cc94cde528 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -1,4 +1,5 @@
-name: Windows Rtools44
+# Note that the workflows below use Powershell (pwsh) as they were originally written for Windows runners.
+name: Rtools & ARM64 CI
 
 on:
   pull_request:
@@ -20,101 +21,28 @@ concurrency:
 
 jobs:
   prim-rev:
-    name: prim and rev tests
-    runs-on: windows-latest
+    name: ${{ matrix.config.label }} tests (${{ matrix.os }})
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [windows-latest, ubuntu-24.04-arm]
+        config: [
+          { label: misc, tests: 'test/unit/*_test.cpp test/unit/math/*_test.cpp test/unit/math/memory' },
+          { label: prim, tests: 'test/unit/math/prim' },
+          { label: rev, tests: 'test/unit/math/rev' },
+          { label: fwd, tests: 'test/unit/math/fwd' },
+          { label: 'non-fun mix', tests: 'test/unit/math/mix/core test/unit/math/mix/meta test/unit/math/mix/*_test.cpp' }
+        ]
 
     steps:
     - uses: actions/checkout@v4
     - uses: actions/setup-python@v5
       with:
         python-version: '3.x'
-    - uses: r-lib/actions/setup-r@v2
-      with:
-        r-version: 'release'
-        rtools-version: '44'
 
-    - name: Set path for Rtools44
-      if: runner.os == 'Windows'
-      run: echo "C:/rtools44/usr/bin;C:/rtools44/x86_64-w64-mingw32.static.posix/bin" | Out-File -Append -FilePath $env:GITHUB_PATH -Encoding utf8
-
-    - name: Build Math libs
-      shell: powershell
-      run: |
-        make -f make/standalone math-libs -j2
-    - name: Add TBB to PATH
-      shell: powershell
-      run: echo "D:/a/math/math/lib/tbb" | Out-File -Append -FilePath $env:GITHUB_PATH -Encoding utf8
-    - name: Run prim and rev unit tests
-      shell: powershell
-      run: |
-        python.exe runTests.py -j2 test/unit/*_test.cpp
-        python.exe runTests.py -j2 test/unit/math/*_test.cpp
-        python.exe runTests.py -j2 test/unit/math/prim
-        python.exe runTests.py -j2 test/unit/math/rev
-        python.exe runTests.py -j2 test/unit/math/memory
-
-    - name: Upload gtest_output xml
-      uses: actions/upload-artifact@v4
-      if: failure()
-      with:
-        name: gtest_outputs_xml
-        path: '**/*_test.xml'
-
-  fwd-non-fun-mix:
-    name: fwd tests and non-fun mix tests
-    runs-on: windows-latest
-
-    steps:
-    - uses: actions/checkout@v4
-    - uses: actions/setup-python@v5
-      with:
-        python-version: '3.x'
     - uses: r-lib/actions/setup-r@v2
-      with:
-        r-version: 'release'
-        rtools-version: '44'
-
-    - name: Set path for Rtools44
       if: runner.os == 'Windows'
-      run: echo "C:/rtools44/usr/bin;C:/rtools44/x86_64-w64-mingw32.static.posix/bin" | Out-File -Append -FilePath $env:GITHUB_PATH -Encoding utf8
-
-    - name: Build Math libs
-      shell: powershell
-      run: |
-        make -f make/standalone math-libs -j2
-    - name: Add TBB to PATH
-      shell: powershell
-      run: echo "D:/a/math/math/lib/tbb" | Out-File -Append -FilePath $env:GITHUB_PATH -Encoding utf8
-    - name: Disable running fwd/mix tests
-      shell: powershell
-      run: echo "CXXFLAGS+= -DSTAN_MATH_TESTS_REV_ONLY" | Out-File -Append -FilePath make/local -Encoding utf8
-    - name: Run fwd unit tests and all the mix tests except those in mix/fun
-      shell: powershell
-      run: |
-        python.exe runTests.py test/unit/math/fwd -j2
-        python.exe runTests.py test/unit/math/mix/core -j2
-        python.exe runTests.py test/unit/math/mix/functor -j2
-        python.exe runTests.py test/unit/math/mix/meta -j2
-        python.exe runTests.py test/unit/math/mix/prob -j2
-        python.exe runTests.py test/unit/math/mix/*_test.cpp -j2
-
-    - name: Upload gtest_output xml
-      uses: actions/upload-artifact@v4
-      if: failure()
-      with:
-        name: gtest_outputs_xml
-        path: '**/*_test.xml'
-
-  mix-fun-1:
-    name: mix/fun tests 1
-    runs-on: windows-latest
-
-    steps:
-    - uses: actions/checkout@v4
-    - uses: actions/setup-python@v5
-      with:
-        python-version: '3.x'
-    - uses: r-lib/actions/setup-r@v2
       with:
         r-version: 'release'
         rtools-version: '44'
@@ -124,19 +52,20 @@ jobs:
       run: echo "C:/rtools44/usr/bin;C:/rtools44/x86_64-w64-mingw32.static.posix/bin" | Out-File -Append -FilePath $env:GITHUB_PATH -Encoding utf8
 
     - name: Build Math libs
-      shell: powershell
+      shell: pwsh
       run: |
+        Add-Content make\local "CPPFLAGS=-w -Wno-psabi -Wno-misleading-indentation`n"
         make -f make/standalone math-libs -j2
+
     - name: Add TBB to PATH
-      shell: powershell
+      if: runner.os == 'Windows'
+      shell: pwsh
       run: echo "D:/a/math/math/lib/tbb" | Out-File -Append -FilePath $env:GITHUB_PATH -Encoding utf8
-    - name: Run mix/fun unit tests
-      shell: powershell
+
+    - name: Run ${{ matrix.config.label }} unit tests
+      shell: pwsh
       run: |
-        $MixFunTests = Get-ChildItem -Path test\unit\math\mix\fun\* -Include *.cpp | Resolve-Path -Relative
-        $NumberTests = $MixFunTests.Length
-        $HalfNumberTests = [math]::Floor($NumberTests / 2)
-        python.exe runTests.py $MixFunTests[0..$HalfNumberTests]
+        python runTests.py -j4 ${{ matrix.config.tests }}
 
     - name: Upload gtest_output xml
       uses: actions/upload-artifact@v4
@@ -145,16 +74,23 @@ jobs:
         name: gtest_outputs_xml
         path: '**/*_test.xml'
 
-  mix-fun-2:
-    name: mix/fun tests 2
-    runs-on: windows-latest
+  mix-fun:
+    name: mix fun and prob tests ${{ matrix.group }} (${{ matrix.os }})
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [windows-latest, ubuntu-24.04-arm]
+        group: [1, 2, 3, 4, 5]
 
     steps:
     - uses: actions/checkout@v4
     - uses: actions/setup-python@v5
       with:
         python-version: '3.x'
+
     - uses: r-lib/actions/setup-r@v2
+      if: runner.os == 'Windows'
       with:
         r-version: 'release'
         rtools-version: '44'
@@ -164,20 +100,32 @@ jobs:
       run: echo "C:/rtools44/usr/bin;C:/rtools44/x86_64-w64-mingw32.static.posix/bin" | Out-File -Append -FilePath $env:GITHUB_PATH -Encoding utf8
 
     - name: Build Math libs
-      shell: powershell
+      shell: pwsh
       run: |
-        Add-Content make\local "O=1`n"
+        Add-Content make\local "CPPFLAGS=-w -Wno-psabi -Wno-misleading-indentation`n"
         make -f make/standalone math-libs -j2
+
     - name: Add TBB to PATH
-      shell: powershell
+      if: runner.os == 'Windows'
+      shell: pwsh
       run: echo "D:/a/math/math/lib/tbb" | Out-File -Append -FilePath $env:GITHUB_PATH -Encoding utf8
+
     - name: Run mix/fun unit tests
-      shell: powershell
+      shell: pwsh
       run: |
-        $MixFunTests = Get-ChildItem -Path test\unit\math\mix\fun\* -Include *.cpp | Resolve-Path -Relative
-        $NumberTests = $MixFunTests.Length
-        $HalfNumberTests = [math]::Floor($NumberTests / 2)
-        python.exe runTests.py $MixFunTests[($HalfNumberTests + 1)..($NumberTests - 1)]
+        $MixFunProbTests = Get-ChildItem -Path test\unit\math\mix\fun\*, test\unit\math\mix\prob\* -Include *.cpp | Resolve-Path -Relative
+        $NumberTests = $MixFunProbTests.Length
+        $FifthNumberTests = [math]::Floor($NumberTests / 5)
+
+        $MixFunProbTestsArray = @( `
+          $MixFunProbTests[0..($FifthNumberTests - 1)], `
+          $MixFunProbTests[$FifthNumberTests..(2 * $FifthNumberTests - 1)], `
+          $MixFunProbTests[(2 * $FifthNumberTests)..(3 * $FifthNumberTests - 1)], `
+          $MixFunProbTests[(3 * $FifthNumberTests)..(4 * $FifthNumberTests - 1)], `
+          $MixFunProbTests[(4 * $FifthNumberTests)..($NumberTests - 1)] `
+        )
+
+        python runTests.py -j2 $MixFunProbTestsArray[(${{ matrix.group }} - 1)]
 
     - name: Upload gtest_output xml
       uses: actions/upload-artifact@v4
diff --git a/stan/math/prim/fun/owens_t.hpp b/stan/math/prim/fun/owens_t.hpp
index 1855ce7827d..e34a45abc3a 100644
--- a/stan/math/prim/fun/owens_t.hpp
+++ b/stan/math/prim/fun/owens_t.hpp
@@ -3,6 +3,7 @@
 
 #include <stan/math/prim/meta.hpp>
 #include <stan/math/prim/functor/apply_scalar_binary.hpp>
+#include <stan/math/prim/fun/boost_policy.hpp>
 #include <boost/math/special_functions/owens_t.hpp>
 
 namespace stan {
@@ -55,7 +56,9 @@ namespace math {
  * @param a Second argument
  * @return Owen's T function applied to the arguments.
  */
-inline double owens_t(double h, double a) { return boost::math::owens_t(h, a); }
+inline double owens_t(double h, double a) {
+  return boost::math::owens_t(h, a, boost_policy_t<>());
+}
 
 /**
  * Enables the vectorized application of the owens_t