Does *#21# show if your phone is hacked? What it really does

What *#21# actually does

*#21# is a status check for one carrier setting: forward all calls. It’s an old GSM “interrogation code” that your phone sends to the network, and the network replies with whether that forwarding is on. When USA Today fact-checked the viral claim in July 2020, a Google security spokesperson called it “just call forwarding.” Apple’s iPhone PR manager said a tapped phone has nothing to do with forwarding settings, “aside from social media memes.”

There’s one thing the meme gets half right. Forwarding can be abused. If someone switches it on for your line, your calls ring their phone instead of yours. That includes the automated calls some banks use to read out a login code. So a forwarding number you don’t recognize is worth fixing. It still isn’t proof your phone is hacked.

What each viral code does on US carriers

Each viral code reads or changes forwarding. None of them scans the phone. Support varies by carrier, so a code that works on one network may just play an error message on another.

Code	What it does	Notes (as of October 2026)
*#21#	Shows whether all calls are forwarded, and to what number	A status check only; changes nothing
#61#, #62#, *#67#	Show forwarding for unanswered calls, phone off or no signal, and busy line	A number here is usually your voicemail (InfoSec Monkey)
*#002#	Not listed on AT&T’s or Verizon’s help pages	Results vary; use the four codes above instead
##002#	Cancels every kind of call forwarding at once (InfoSec Monkey)	Can switch off voicemail forwarding too
21 + number + # / #21#	Turns forward-all on / off	AT&T’s own wireless help
72 + number / 73	Turns forwarding on / off (*71 for unanswered calls only)	Verizon’s own help

AT&T’s device help says to turn forwarding on with 21 plus the 10-digit number and #, and off with #21#. Verizon’s FAQ and its list of star codes use *72 to turn it on and *73 to turn it off, and that list doesn’t include *#21#. The GSM codes in the top rows come from decades-old 3GPP standards, and support still varies by carrier. On T-Mobile or any other carrier, check its support site or call it to confirm which codes work.

Apple told USA Today in 2020 that on carriers that don’t support these codes, “like Verizon for example”, you may just hear a recording saying the number is wrong. That recording doesn’t mean anything is wrong with your phone.

Seeing a number usually isn’t a bad sign. GSM networks send your unanswered calls to voicemail through the *#61#, *#62# and *#67# settings, so the number there is often your carrier’s voicemail system.

Worry if *#21# shows forward-all switched on to a number you don’t know, or if your phone has stopped ringing for calls. Before you use ##002#, know that it can switch off voicemail forwarding too. If voicemail stops picking up afterward, call your carrier or set voicemail up again.

On an iPhone you can often skip the codes. As of October 2026, Apple’s guide puts the switch at Settings > Apps > Phone > Call Forwarding, and a Call Forwarding icon shows in the status bar while it’s on. Apple says the setting is for GSM networks; if your carrier doesn’t offer it there, use the carrier’s codes or call it. On Android, look for Call forwarding in the Phone app’s settings. The exact menu varies by phone maker.

The real risk: being told to dial a code

The bigger risk is being talked into switching forwarding on yourself. In the version a Maryland sheriff’s office described in September 2026, a caller posing as your bank says they’ll transfer you to the fraud department and tells you to dial *72 plus a 10-digit number. That forwards all your calls to the scammer, who can then have your bank’s verification calls and codes sent to them.

Apple now builds in a guard. Its iPhone guide says the phone alerts you and blocks links in messages, email, webpages or apps that ask you to turn on call forwarding. Treat any request to dial a code starting with * or # as a red flag. If you already did it, the sheriff’s office says to dial *73 to cancel the forwarding. AT&T’s help lists #21# as its off code, and you can also switch off Call Forwarding in your phone’s settings. Then call your bank on the number printed on your card, and change your account passwords.

Checks that actually find a hacked phone

There’s no dial code for spyware. The FTC lists the real warning signs of malware. Among them: the device slows down, freezes or crashes. Pop-up ads appear where they shouldn’t. Messages go out that you didn’t send. Settings tools stop working.

These free checks cover what a code can’t:

iPhone Safety Check. Settings > Privacy & Security > Safety Check, on iOS 16 or later. It lets you review who and what has access, remove devices connected to your Apple Account, and change your passcode and Apple Account password.
Google devices list. Go to your Google Account, tap Security & sign-in, then Manage all devices. Sign out of anything that isn’t yours.
Google Play Protect. It’s on by default and scans apps for harmful behavior. In the Play Store, tap your profile icon, then Play Protect, then Settings, and check that Scan apps with Play Protect is on.

If you tapped a link before all this started, our guide on what happens if you click a link in a scam text walks through the next steps. If a stranger asked you to read back a code, see someone asked for my Google Voice verification code. Worried about a computer as well? See how to check a laptop for a keylogger.

What to do next

Check forwarding the easy way: Settings > Apps > Phone > Call Forwarding on iPhone (where your carrier offers it), or dial *#21# (it works on many carriers, not all). Turn off anything you didn’t set.
Run Safety Check on iPhone, or review Manage all devices in your Google Account, and remove devices you don’t recognize.
Update your phone and apps, and keep Google Play Protect switched on if you use Android.
Never dial a * or # code because a caller or text told you to. Hang up and call the company on a number you already trust.

Does dialing *#21# tell you if your phone is hacked?