Vivo X21 comes with Android 8.1 (Oreo) OS, 6.28 inches Super AMOLED LCD capacitive touchscreen, 16M colors and 1080 x 2280 pixels resolution + 402 PPI pixel density, It has Black, Aurora White and Ruby Red color, Dual SIM (Nano-SIM, dual stand-by) Slot supports 2G, 3G and 4G LTE network.
The smartphone has Dual 12 MP f/1.8 + 5 MP, autofocus rear camera having geo-tagging, touch focus, face detection, HDR and panorama features and 12 MP f/2.0 front camera for selfie experience.
Vivo X21 has Octa-core (4x2.2 GHz Kryo 260 & 4x1.8 GHz Kryo 260) processor, Qualcomm SDM660 Snapdragon 660 chipset and Adreno 512 GPU.
It has 6GB RAM and 64GB/128GB internal Storage, microSD, up to 256 GB card slot. It brings Bluetooth 5.0, A2DP, LE + microUSB v2.0 and 3.5 mm Audio jack.
Here is 3200mAh battery with fast charging but no wireless charger support.
The smartphone has Fingerprint (rear-mounted), accelerometer, proximity and compass sensors.