WhatsApp is a global messaging application that has exploded in popularity over the past several years. However, despite the fact that the mobile app spent a considerable amount of time under the scrutiny of the public eye, there are still some surprising facts that many people don’t know.

Number 1: The Pope Used WhatsApp. Pope Francis used the app in 2015 to send messages to users during Lent.

Number 2: Argentina Likes the App. An impressive 84% of mobile phone users in Argentina use WhatsApp. The app tends to be more beneficial for people who live in Europe and South America because they can use it to avoid daily messaging fees.

Number 3: The Company Is Worth More Than NASA’s Budget. In 2014, Facebook bought WhatsApp for $19 billion. This is more than NASA’s budget, which was notoriously high that year. Their budget was $17 billion.

Number 4: Facebook’s Acquisition of the App Was Finalized on Valentine’s Day. How romantic! Koum went over to Facebook co-founder Mark Zuckerberg’s house on Valentine’s Day in 2014 to let him know that he accepted his proposal.

Number 5: Koum Almost Abandoned It. After launching the app in 2009, there were several logistical issues that caused it to become stuck or crash. Founder Jan Koum became so frustrated with the app that he almost abandoned it; however, his co-founder Brian Acton encouraged him to stick with it.

Number 6: India Is Its Largest User. Up to 10% of the app’s users are based in India. This makes India the largest client base in terms of the actual number of users.

Number 7: It Only Has 55 Employees. The app must be paying its employees quite handsomely because there are only about 55 of them. Its founders might be billionaires, but we bet at least some of these employees are millionaires.

Number 8: Its Founders Haven’t Spent a Dime on Marketing. According to an infographic, the app hasn’t spent anything on digital marketing. Instead, the app relies on its promises of no ads and no gimmicks to keep it going strong.

Number 9: WhatsApp Became a Paid Service to Slow the App’s Growth. Though most app creators get excited to see their baby become so popular, this wasn’t necessarily the case with WhatsApp. Founders Koum and Acton switched it to a paid service because it was growing too quickly and they had to cover the costs of sending verification texts.

Number 10: 30 Billion Messages Are Sent and Received Every Day. WhatsApp is the world’s number one messaging app, and more than 30 billion messages are sent and received every single day.

Number 11: WhatsApp Wouldn’t Exist Without Yahoo. Both of the app’s founders worked at Yahoo before making the app. Before making the app, Koum relied on his savings he earned with Yahoo to get by, so without those savings, who knows what he’d be doing now.

Number 12: Its Founders Literally Had to Be Hunted Down by Investors. Sequoia Capital invested $7 million in the app in 2011; however, Sequoia partner Jim Goetz struggled to contact Koum and Acton to propose this to them. According to Goetz, the firm couldn’t find an address for the two and only knew that they were based in Mountain View, California. He had partners visit the city and walk around to try and locate them.

Number 13: The Founders Were Rejected by Facebook. Despite the fact that Facebook bought the app for $19 billion in 2014, the app’s founders, Jan Koum and Brian Acton, both applied to Facebook before making WhatsApp and were rejected. Facebook could have saved a lot of money by hiring them.