@BDforever
According to SIPRI Arms Transfers database 28 Mi-17/8 have been exported to Bangladesh:
Trade Registers
Russia:
R: Bangladesh 4 Mi-8/Mi-17/Hip-
H Helicopter (1992) 1993 (4)
Mi-17 version
8 Mi-8/Mi-17/Hip-H
Helicopter (1995) 1995 8 Mi-17
version
3 Mi-8/Mi-17/Hip-H
Helicopter (1998) 1999 3 $4 m
deal (not incl value of trade-in of 7 ex-
Bangladeshi Mi-8 helicopters)
3 Mi-8/Mi-17/Hip-H
Helicopter 2004 2007 3 BDT78
m ($1.3 m) deal; Mi-171 armed
version.
3 Mi-8/Mi-17/Hip-H
Helicopter 2010 2011 ; Mi-171 armed
version.
USSR
R: Bangladesh
(7) Mi-8T/Hip-C
Helicopter (1973) 1974 (7)
1 Mi-17 crashed in 2002 killing 4 crew members and 7 Mi-8 received in 70s are in storage.
So there are 20 in service. 5 more are on order
Edit: Bangladesh Navy has ordered 3 Harbin Z-9 (ASW version, number on order could be 2).