What is country code of Bangladesh?

Bangladesh is country code +880.

When calling from outside Bangladesh, you must drop the trunk prefix '0' from the Bangladeshi number. For example, Dhaka's area code 02 becomes +880 2. Although this has the same effect as prefixing the domestic number with '+88', it is incorrect to say that Bangladesh is country code +88.

Mobile numbers begin with +880 1. VoIP numbers begin with +880 96.

(The plus sign means "insert your international access prefix here." From a GSM mobile phone, you can enter the number in full international format, starting with the plus sign. The most common prefix is 00, but North America (USA, Canada, etc.) uses 011, Japan uses 010, Australia uses 0011, and many other countries use different prefixes.)