Russia had left Prussia with a larges arms factory that manufactured the new Russian helmet and body armor but also a myriad of small arms and ammunition. This facility is of course state owned by the Republic. Workers are recruited through the office of Republic Service as in any republic job, and of course service leads to citizenship.
Russia has agreed to provide assistance in the construction of one nuclear power plant, but the Chancellors office is secretly planning on building more, to ween the country off of heating oil from Russia in the event that relations there ever sour.
There are no taxes on corporations in Prussia. Corporations are not recognized as an entity as in other nations and thus are not subject to taxation but must pay for an annual privilege license. This has led to the mass immigration of corporate business into Prussia, particularly Koenigsberg where construction of skyscrapers are underway. In addition to their privilege license any business that operates and has facilities in Prussia must have a workforce of at least 75% Prussian citizens and civilians at those facilities and of course the rest of their workforce must be approved for entry into Prussia via a work visa. This situation has led to a fast influx of money into Prussia. Koenigsberg is likened unto Hong Kong and is being referred to as such in business and money circles. Also Prussian banks do not have to reveal anything about their clients, which has taken much business from Switzerland.
The current population is expanding, but there is hardly any illegal immigration since legal penalties are harsh in Prussia and border enforcement is taken seriously.