diff --git a/index.js b/index.js
index c5c3d87..4399473 100644
--- a/index.js
+++ b/index.js
@@ -37,6 +37,10 @@ export default class GitHubProject {
   constructor(options) {
     const { owner, number, fields = {} } = options;
 
+    if (Number.isNaN(number)) {
+      throw new TypeError("The number option must be a valid number");
+    }
+
     // set octokit either from `options.octokit` or `options.token`
     const octokit =
       "token" in options
diff --git a/test/constructor.test.js b/test/constructor.test.js
index 6378b53..f340282 100644
--- a/test/constructor.test.js
+++ b/test/constructor.test.js
@@ -50,3 +50,15 @@ test("constructor with token", (t) => {
 
   t.true(project.octokit instanceof Octokit);
 });
+
+test("rejects NaN as the number option", (t) => {
+  t.throws(
+    () =>
+      new GitHubProject({
+        owner: "owner",
+        number: NaN,
+        octokit: new Octokit(),
+      }),
+    { message: "The number option must be a valid number" },
+  );
+});