As character names:

U+24F4 NEGATIVE CIRCLED NUMBER TWENTY character (⓴)

As raw characters:

⓴

As a string of HTML entities:

⓴

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 147, hex 0x93, octal \223, binary 10010011
This is continuation byte 1, expecting 1 more.

Byte number 3 is decimal 180, hex 0xB4, octal \264, binary 10110100
This is continuation byte 2, expecting 0 more.

U+24F4	NEGATIVE CIRCLED NUMBER TWENTY