The grim milestone was reached in the early hours of Tuesday morning, Irish time, with 20,011,186 cases worldwide.
The total number of global coronavirus deaths stands at 734,664, according to experts at Johns Hopkins, the American university whose aggregated tally has become the main reference for monitoring the disease.
The US has also suffered the most deaths at 163,331, while there have been 101,000 in Brazil, 52,000 in Mexico, 46,611 in the UK and more than 44,000 in India.
The number of cases in the US has just passed five million, Brazil has reached three million, with 2.2 million in India, almost 900,000 in Russia and 560,000 in South Africa.
Ireland has 26,768 cases, putting it 64th on the list. The UK has 313,392 cases according to the university, putting it 12th on the list, just behind Spain.
Health officials believe the real figure of cases worldwide is in fact far higher than the Johns Hopkins tally, due to testing limitations and the fact as many as 40 per cent of people infected have no symptoms.
The death tolls from some countries who suffered hardest in the early months of the pandemic appear to have stabilised, with Italy ranking behind India in sixth place with 35,209 deaths, France next with 30,327, ahead of Spain on 28,576.
Peru ranks ninth, with the second-highest fatality toll in South America, at 21,072.
Despite having the fourth-highest number of cases, Russia sits only 11th by deaths, with 14,973.
Similarly South Africa ranks only 13th by deaths, with 10,621, despite sitting fifth by number of cases.
