diff --git a/yaml/_type/int.ts b/yaml/_type/int.ts
index 494cf4622..f0d2e4b37 100644
--- a/yaml/_type/int.ts
+++ b/yaml/_type/int.ts
@@ -131,6 +131,7 @@ function constructYamlInteger(data: string): number {
 }
 
 function isInteger(object: unknown): object is number {
+  if (object instanceof Number) object = object.valueOf();
   return typeof object === "number" && object % 1 === 0 &&
     !isNegativeZero(object);
 }
@@ -142,21 +143,31 @@ export const int: Type<"scalar", number> = {
   kind: "scalar",
   predicate: isInteger,
   represent: {
-    binary(obj: number): string {
-      return obj >= 0
-        ? `0b${obj.toString(2)}`
-        : `-0b${obj.toString(2).slice(1)}`;
+    // deno-lint-ignore ban-types
+    binary(object: number | Number): string {
+      const value = object instanceof Number ? object.valueOf() : object;
+      return value >= 0
+        ? `0b${value.toString(2)}`
+        : `-0b${value.toString(2).slice(1)}`;
     },
-    octal(obj: number): string {
-      return obj >= 0 ? `0${obj.toString(8)}` : `-0${obj.toString(8).slice(1)}`;
+    // deno-lint-ignore ban-types
+    octal(object: number | Number): string {
+      const value = object instanceof Number ? object.valueOf() : object;
+      return value >= 0
+        ? `0${value.toString(8)}`
+        : `-0${value.toString(8).slice(1)}`;
     },
-    decimal(obj: number): string {
-      return obj.toString(10);
+    // deno-lint-ignore ban-types
+    decimal(object: number | Number): string {
+      const value = object instanceof Number ? object.valueOf() : object;
+      return value.toString(10);
     },
-    hexadecimal(obj: number): string {
-      return obj >= 0
-        ? `0x${obj.toString(16).toUpperCase()}`
-        : `-0x${obj.toString(16).toUpperCase().slice(1)}`;
+    // deno-lint-ignore ban-types
+    hexadecimal(object: number | Number): string {
+      const value = object instanceof Number ? object.valueOf() : object;
+      return value >= 0
+        ? `0x${value.toString(16).toUpperCase()}`
+        : `-0x${value.toString(16).toUpperCase().slice(1)}`;
     },
   },
   resolve: resolveYamlInteger,
diff --git a/yaml/stringify_test.ts b/yaml/stringify_test.ts
index a278b6c26..9c1638446 100644
--- a/yaml/stringify_test.ts
+++ b/yaml/stringify_test.ts
@@ -77,11 +77,18 @@ Deno.test({
 });
 
 Deno.test({
-  name: "stringify() serializes integers",
+  name: "stringify() handles integers",
   fn() {
     assertEquals(stringify(42), "42\n");
     assertEquals(stringify(-42), "-42\n");
 
+    assertEquals(stringify(new Number(42)), "42\n");
+    assertEquals(stringify(new Number(-42)), "-42\n");
+  },
+});
+Deno.test({
+  name: "stringify() handles integers with styles option",
+  fn() {
     // binary, octal, and hexadecimal can be specified in styles options
     assertEquals(
       stringify(42, { styles: { "!!int": "binary" } }),
@@ -91,6 +98,10 @@ Deno.test({
       stringify(-42, { styles: { "!!int": "binary" } }),
       "-0b101010\n",
     );
+    assertEquals(
+      stringify(new Number(42), { styles: { "!!int": "binary" } }),
+      "0b101010\n",
+    );
     assertEquals(
       stringify(42, { styles: { "!!int": "octal" } }),
       "052\n",
@@ -99,6 +110,10 @@ Deno.test({
       stringify(-42, { styles: { "!!int": "octal" } }),
       "-052\n",
     );
+    assertEquals(
+      stringify(new Number(42), { styles: { "!!int": "octal" } }),
+      "052\n",
+    );
     assertEquals(
       stringify(42, { styles: { "!!int": "hexadecimal" } }),
       "0x2A\n",
@@ -107,6 +122,15 @@ Deno.test({
       stringify(-42, { styles: { "!!int": "hexadecimal" } }),
       "-0x2A\n",
     );
+    assertEquals(
+      stringify(new Number(42), { styles: { "!!int": "hexadecimal" } }),
+      "0x2A\n",
+    );
+    assertThrows(
+      () => stringify(42, { styles: { "!!int": "camelcase" } }),
+      TypeError,
+      '!<tag:yaml.org,2002:int> tag resolver accepts not "camelcase" style',
+    );
   },
 });