*#21# meaning
*#21# meaning

Have you ever stumbled upon a series of numbers and symbols on your phone and wondered what they signify? Welcome to the realm of USSD codes, the short codes that hold a world of functions within them. Like entering a cheat code in a video game, USSD codes can unlock a variety of features on your phone. Code *#21# is particularly famous because of a viral meme / internet hoax behind it.

What is *#21#?

The Purpose Behind It

*#21# is a specific Unstructured Supplementary Service Data (USSD) code that, when entered, allows you to check if call forwarding is enabled on your mobile device. Think of it as a flashlight, letting you peek into a specific setting on your phone.

The Viral Internet Hoax

Every few years the hoax surrounding code: *#21# goes viral. It goes something along the lines of – you type in the code into your iPhone or Samsung (Android) phone and if it outputs values your phone has been tapped or hacked, etc.

This is simply a meme. As explained above that code is to output your call forwarding status. It isn’t tied to any malicious hacking or malware/spyware on your phone.

How to Use It

Using *#21# is as simple as dialing a phone number. Here’s how:

  1. Open your phone’s dialer.
  2. Type in *#21#.
  3. Press the call or dial button.
  4. You’ll see a prompt displaying the status of your call forwarding settings.

The Importance of Call Forwarding

Imagine you’re on vacation and you don’t want to miss important work calls. Call forwarding enables you to direct incoming calls to another number. It’s like having a virtual assistant ensuring you never miss a beat, whether for business or personal reasons.

Situations When *#21# is Useful

  1. Traveling Overseas: Before jetting off, checking your call forwarding status ensures you’re reachable on another device or number.
  2. Switching Phones: Transitioning to a new device? This code helps confirm if calls will be forwarded correctly.
  3. For Peace of Mind: If you’re unsure about your settings or suspect someone might have tampered with them, *#21# offers a quick check.

Safety and Privacy Concerns

Recognizing Unauthorized Usage

In today’s digital age, ensuring our mobile devices are secure is paramount. Unauthorized call forwarding can be a sign of foul play. If, after dialing *#21#, you notice unexpected call forwarding, it’s time to investigate.

Keeping Your Mobile Secure

Always ensure your mobile device has the latest software updates. Using strong, unique passcodes and regularly reviewing your settings can also bolster security.


USSD codes, especially *#21#, are more than mere numbers. They’re a gateway into the intricate workings of your phone, ensuring you have control, awareness, and most importantly, peace of mind. Knowledge is power, and in this case, it’s just a dial away!


  1. *Can I use #21# on any mobile device?
    • Most GSM mobile devices support this code. However, some carriers or regions may have restrictions.
  2. *Is there any cost associated with using #21#?
    • Typically, USSD codes like *#21# are free to use, but always consult with your carrier to ensure there are no hidden charges.
  3. How can I set up call forwarding?
    • Call forwarding setup varies by device and carrier. It’s often available in the phone or call settings menu. Alternatively, there are specific USSD codes for activating and deactivating call forwarding.
  4. What if I notice unauthorized call forwarding?
    • Immediately deactivate it through your settings or by using the appropriate USSD code. Consider changing your passcodes and consult your carrier for further steps.
  5. *Are there other similar codes to #21#?
    • Yes, there are numerous USSD codes to check different phone settings and services. Check with your carrier for a comprehensive list.
Eric Chan

Hi! I’m Eric and I work on the knowledge base at GadgetMates.com.  You can see some of my writings about technology, cellphone repair, and computer repair here.

When I’m not writing about tech I’m playing with my dog or hanging out with my girlfriend.

Shoot me a message at ericchan@gadgetmates.com if you want to see a topic discussed or have a correction on something I’ve written.

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