Example of conversion (mix of previous posts, thanks for inspiration):
media_player.samsung_ue40d7000
supported_features: 20281
20281 (decimal) = 100 1111 0011 1001 (binary)
20281 equals to
SUPPORT_PAUSE = 1
SUPPORT_VOLUME_MUTE = 8
SUPPORT_PREVIOUS_TRACK = 16
SUPPORT_NEXT_TRACK = 32
SUPPORT_TURN_OFF = 256
SUPPORT_PLAY_MEDIA = 512
SUPPORT_VOLUME_STEP = 1024
SUPPORT_SELECT_SOURCE = 2048
SUPPORT_PLAY = 16384
(extracted from https://github.com/home-assistant/core/blob/ff9de687c07e8df3ec25dc72e9fb11dbcd2ef0f5/homeassistant/components/media_player/const.py)
How? Easy. Open a calculator that it shows binary and decimal at same time (programmer mode).
You need type in binary and convert to decimal (I only type a 1 and several 0 according to position):
1 (binary) = 1 (decimal)
1000 (binary) = 8 (decimal)
1 0000 (binary) = 16 (decimal)
10 0000 (binary) = 32 (decimal)
1 0000 0000 (binary) = 256 (decimal)
10 0000 0000 (binary) = 512 (decimal)
100 0000 0000 (binary) = 1024 (decimal)
1000 0000 0000 (binary) = 2048 (decimal)
100 0000 0000 0000 (binary) = 16384 (decimal)
Check: 1 + 8 + 16 + 32 + 256 + 512 + 1024 + 2048 + 16384 = 20281