As character names:

U+25EF LARGE CIRCLE character (◯)

As raw characters:

◯

As a string of HTML entities:

◯

Decoder output:

Byte number 1 is decimal 226, hex 0xE2, octal \342, binary 11100010
This is the first byte of a 3 byte sequence.

Byte number 2 is decimal 151, hex 0x97, octal \227, binary 10010111
This is continuation byte 1, expecting 1 more.

Byte number 3 is decimal 175, hex 0xAF, octal \257, binary 10101111
This is continuation byte 2, expecting 0 more.

U+25EF	LARGE CIRCLE
	x (combining enclosing circle - 20DD)
	x (white circle - 25CB)
	x (black large circle - 2B24)
	x (heavy large circle - 2B55)
	x (ideographic number zero - 3007)