| Hardware and OS vivo X21 UD |
| Operating system: | Android 8.1 (Oreo); Funtouch 4 |
| Processor: | Octa-core (4x2.2 GHz Kryo 260 & 4x1.8 GHz Kryo 260) |
| Chipset: | Qualcomm SDM660 Snapdragon 660 (14 nm) |
| GPU: | Adreno 512 |
| Internal memory: | 128 GB, 6 GB RAM |
| External memory: | microSD, up to 256 GB (uses SIM 2 slot) |
| Display vivo X21 UD |
| Type: | Super AMOLED |
| Size: | 6.28" inc |
| Resolution: | 1080 x 2280 px |
| Touchscreen: | capacitive touchscreen |
| Screen-to-Body Ratio: | 85.2% |
| Display area: | 98.4 cm2 |
| Display aspect ratio: | 19:9 (height:width) |
| Pixel Density: | 402 PPI |
| Colors: | 16M |
| Connectivity vivo X21 UD |
| 2G Network: | GSM 850 / 900 / 1800 / 1900 - SIM 1 & SIM 2 |
| 3G Network: | HSDPA 850 / 900 / 1900 / 2100 |
| 4G Network: | LTE band 1(2100), 2(1900), 3(1800), 5(850), 8(900), 34(2000), 38(2600), 39(1900), 40(2300), 41(2500) |
| Wi-Fi: | Wi-Fi 802.11 a/b/g/n/ac, dual-band, WiFi Direct, hotspot |
| Network: | GSM / CDMA / HSPA / LTE |
| SIM card: | Hybrid Dual SIM (Nano-SIM, dual stand-by) |
| Bluetooth: | 5.0, A2DP, LE |
| Edge: | Yes |
| GPRS: | Yes |
| GPS: | Yes, with A-GPS, GLONASS |
| Speed: | HSPA 42.2/5.76 Mbps, LTE-A (2CA) Cat6 300/50 Mbps |
| USB: | microUSB 2.0, USB On-The-Go |
| Camera vivo X21 UD |
| Main camera: | 12 MP,
Dual |
| Specs: | 12 MP, f/1.8, 1/2.55', 1.4µm, dual pixel PDAF
-5 MP, f/2.4, depth sensor |
| Features: | LED flash, HDR, panorama |
| Video: | 1080p@30fps |
| Selfie camera: | 12 MP,
Single |
| Specs: | 12 MP, f/2.0 |
| Video: | 1080p@30fps |
| Multimedia vivo X21 UD |
| 3.5 mm Jack: | Yes |
| Radio: | FM radio |
| Design vivo X21 UD |
| Colors: | Black, Ruby Red |
| Body build: | Front glass, aluminum body |
| Dimensions: | 154.5 x 74.8 x 7.4 mm |
| Weight: | 156.2 g |
| Battery vivo X21 UD |
| Battery capacity: | 3200 mAh, Non-removable Li-Ion |
| Other vivo X21 UD |
| Release date: | 2018, March |
| Sensors: | Fingerprint (under display), accelerometer, proximity, compass |
