The Samsung Galaxy S21 is considered a flagship device due to its high-end features and premium build quality. Here are some key aspects that make it a flagship:

Display:

• 6.2-inch Dynamic AMOLED 2X
• Full HD+ resolution (2400 x 1080 pixels)
• 120Hz adaptive refresh rate
• HDR10+ support
• Peak brightness: 1300 nits

Processor:

• Chipset:
  • Exynos 2100 (5nm) – Global
  • Snapdragon 888 (5nm) – USA/China
• Octa-core CPU:
  • 1 x 2.9 GHz Cortex-X1
  • 3 x 2.8 GHz Cortex-A78
  • 4 x 2.2 GHz Cortex-A55
• GPU: Mali-G78 MP14 (Exynos) / Adreno 660 (Snapdragon)

RAM:

• 8GB

Internal Storage:

• 128GB or 256GB
• Non-expandable (no microSD slot)

Operating System:

• Android 11 out of the box
• Upgradable to Android 13 with One UI 5

Cameras:

• Rear Cameras:
  • 12 MP wide (f/1.8, OIS)
  • 12 MP ultra-wide (f/2.2, 120° field of view)
  • 64 MP telephoto (f/2.0, 3x hybrid zoom, OIS)
• Front Camera:
  • 10 MP (f/2.2)

Battery:

• 4000 mAh
• 25W wired charging (USB-C)
• 15W wireless charging
• 4.5W reverse wireless charging

Connectivity:

• 5G support
• Wi-Fi 6 for high-speed connectivity
• Bluetooth 5.0
• USB Type-C 3.2
• NFC

Build and Durability:

• Gorilla Glass Victus on the front
• Plastic back with aluminum frame
• IP68 water and dust resistance

Audio:

• Stereo speakers with Dolby Atmos
• No 3.5mm headphone jack

Security:

• Ultrasonic in-display fingerprint sensor
• Face recognition

Colors:

• Phantom Gray, Phantom White, Phantom Violet, Phantom Pink

Additional Features:

• Samsung DeX support
• Samsung Knox for enhanced security
• Wireless PowerShare for charging accessories