Debreceni EAC may refer to:

• Debreceni EAC (football), the football section of the Hungarian multi-sports club
• Debreceni EAC (basketball), the basketball section of the Hungarian multi-sports club

• 646 (character set)
• 646 in Japan
• 646 (year)
• 647 AD
• 6"/47 caliber Mark 16 gun
• 647 CE
• 6"/47 Mark 16
• 647th Regional Support Group
• 647 (year)
• 6486th Air Base Wing
• 648 AD
• 648 CE
• 648 (year)
• 6/49
• 649 AD
• 649 CE
• 6/49 (disambiguation)
• 649 (year)
• 64b/66b
• 64-Bit
• 64-bit binary floating-point format
• 64-bit CPU
• 64-bit decimal floating-point format
• 64-bit floating point format
• 64-bit floating-point format