For numbers up to 2^53 the type double represents the digits exactly. This is 9-0e15. See flintmax.
Your example n=1.76536927729736e+16 exceed this limit. Therefore doubles are not useful fpr your needs. You cannot even store the value exactly in a double. Maybe you need an UINT8 vector containing the digits, or a CHAR vector.
It does not matter, if the value is displayed in the e notation or not, because this can be controlled by the command: format