As character names:

U+2146 DOUBLE-STRUCK ITALIC SMALL D character (ⅆ)

As raw characters:

ⅆ

As a string of HTML entities:

ⅆ

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 133, hex 0x85, octal \205, binary 10000101
This is continuation byte 1, expecting 1 more.

Byte number 3 is decimal 134, hex 0x86, octal \206, binary 10000110
This is continuation byte 2, expecting 0 more.

U+2146	DOUBLE-STRUCK ITALIC SMALL D
	* sometimes used for the differential
	# <font> 0064 latin small letter d