int and BIGNUM operations?

[Eugene N]

Dear sirs

I am looking for a way to perform a set of heterogeneous operations, with
some parameters being BIGNUM and some just 32 bit integers.
for example, multiply a bignum by 2, increment a bignum by 1, find a result
of BIGNUM modulo 3, etc.

How can i do it, without initialising bignums to 2, 1 or 3?

Thanks, very much in your debt,
Neverov E.