- Africa's largest economy, biggest oil producer and most populous nation
- Oil-rich, but facing worst economic crisis in years after falling oil prices
- 62.6% of its 170 million population live in poverty
- Average annual earnings - $1280 (£850)
It also revealed that some employees were receiving salaries from multiple sources.
Some 23,846 non-existent workers were removed from the payroll, an adviser to the finance minister was quoted by Reuters as saying.
Periodic checks and electronic audit techniques will be periodically carried out to prevent new frauds, the ministry said.
Officials have said the savings resulted from the anti-corruption measures will help the country tackle its crisis and prevent job cuts.