| Brand | BBK |
| Model | Vivo X21 Dual SIM TD-LTE TW HK SG 128GB |
| Released | 2018 May 6 |
| Announced | 2018 May 1 |
| Hardware Designer | BBK Electronics |
| Manufacturer | BBK Electronics |
| General Extras | Haptic touch feedback |
| Device Category | Smartphone |
| Width | 74.78 mm |
| Height | 154.45 mm |
| Depth | 7.37 mm |
| Dimensions | 2.94×6.08×0.29 inches |
| Mass | 156.2 g |
| Platform | Android |
| Operating System | Google Android 8.1 (Oreo) |
| Software Extras | Voice Command , Navigation software , Intelligent personal assistant , Face Recognition |
| CPU Clock | 2200 MHz |
| CPU | Qualcomm Snapdragon 660 SDM660, 2017, 64 bit, octa-core, 14 nm, Qualcomm Adreno 512 GPU |
| RAM Type | LPDDR4 SDRAM |
| RAM Capacity (converted) | 6 GiB RAM |
| Non-volatile Memory Interface | Yes |
| Non-volatile Memory Capacity (converted) | 128 GB ROM |
| Display Notch | 1-notch |
| Display Diagonal | 159.5 mm |
| Resolution | 1080×2280 |
| Horizontal Full Bezel Width | 6.5 mm |
| Display Area Utilization | 85.2% |
| Pixel Density | 402 PPI |
| Display Type | AM-OLED display |
| Display Subtype | Super AM-OLED |
| Number of Display Scales | 16.8M |
| Scratch Resistant Screen | No |
| Graphical Controller | Qualcomm Adreno 512 |
| Dedicated Graphics Memory | 0.25 MiB |
| A/V Out | No |
| Audio Controller | Asahi Kasei AK4376A |
| Microphone(s) | stereo |
| Loudspeaker(s): | mono |
| Audio Output: | 3.5mm |
| Supported Cellular Bands | GSM850 , GSM900 , GSM1800 , GSM1900 , UMTS2100 (B1) , UMTS850 (B5) , UMTS900 (B8) , LTE2100 (B1) , LTE1800 (B3) , LTE850 (B5) , LTE2600 (B7) , LTE900 (B8) , LTE700 (B28) , TD-LTE2600 (B38) , TD-LTE1900 (B39) , TD-LTE2300 (B40) , TD-LTE2500 (B41) bands |
| Supported Cellular Data Links | GPRS , EDGE , UMTS , HSUPA , HSDPA , HSDPA 7.2 , HSPA+ 21.1 , LTE , LTE 100/50 , LTE 150/50 , LTE 300/50 data links |
| SIM Card Slot | Nano-SIM (4FF) |
| Complementary Phone Services | Voice transmission , Voice speaker , Vibrate , Speakerphone , ANC , HD Voice , VoLTE |
| Dual Cellular Network Operation | Dual standby |
| Sec. Supported Cellular Networks: | GSM850 , GSM900 , GSM1800 , GSM1900 |
| Sec. Supported Cellular Data Links: | GPRS , EDGE |
| Sec. SIM Card Slot | Nano-SIM (4FF) |
| Touchscreen Type | Capacitive multi-touch screen |
| Expansion Interfaces | TransFlash , microSD , microSDHC , microSDXC |
| USB | USB 2.0 |
| USB Services | USB charging , USB fast charging , USB Host , USB OTG 1.3 , USB PD |
| USB Connector | USB Micro-AB |
| Bluetooth | Bluetooth 5.0 |
| Wireless LAN | 802.11a , 802.11b , 802.11g , 802.11n , 802.11ac |
| Wireless Services | Wi-Fi Tethering , Wi-Fi Calling |
| FM Radio Receiver | No |
| Complementary Satellite Services | Simultaneous GPS , A-GPS , Geotagging , QuickGPS |
| Supported GLONASS protocol(s) | L1OF |
| Supported BeiDou system (BDS) | B1I BeiDou receiver |
| Camera Placement | Rear |
| Camera Image Sensor | CMOS |
| Image Sensor Pixel Size | 1.28 micrometer |
| Number of effective pixels | 12.2 MP camera |
| Aperture (W) | f/1.80 |
| Zoom | 1.0 x optical zoom |
| Focus | PD AF |
| Video Recording | 1920×1080 pixel |
| Flash | single LED |
| Camera Extra Functions | HDR photo , Slow motion video , Burst mode , Touch focus , Macro mode , Panorama Photo , Face detection , Face retouch |
| Aux. Camera Image Sensor | CMOS |
| Aux. Camera Number of Pixels | 5.0 MP aux. cam |
| Aux. Camera Aperture (W) | f/2.40 |
| Aux. 2 Camera Image Sensor | No |
| Aux. 3 Camera Image Sensor | No |
| Aux. 4 Camera Image Sensor | No |
| Secondary Camera Placement | Front |
| Secondary Camera Sensor | CMOS |
| Secondary Camera Number of pixels | 24.0 MP sec. cam |
| Secondary Aperture (W) | f/2.00 |
| Secondary Camera Extra Functions | HDR photo , Burst mode , Face detection , Face tagging , Face retouch |
| Sec. Aux. Cam. Image Sensor | No |
| Built-in compass | Yes |
| Built-in accelerometer | Yes |
| Built-in gyroscope | Yes |
| Additional sensors | FP sensor , L sensor , P sensor |
| Protection from solid materials | Yes |
| Protection from liquids | Yes |
| Battery | Li-ion polymer (LiPo) |
| Nominal Battery Capacity | 3200 mAh battery |
| Market Countries | HK , Singapore , Taiwan |
| Market Regions | Asia , Southeast Asia |
| Mobile Operator | Chunghwa Telecom Hong Kong CSL Mobile Limited SmarTone Mobile Communications Limited Taiwan Mobile |
| Added | 2024-06-20 |
