PUNE, India (AFP) - Not many people can boast of having candid conversations about planetary conquest with Mr Elon Musk, but for Indian software engineer Pranay Pathole, a friendly chat with the world's richest man is just a tweet away.

Their unlikely online friendship has blossomed since Mr Pathole was a teenager, with the mercurial billionaire responding to him over hundreds of tweets and private messages with headline-making company updates and even life advice.

This week, the two finally met face to face, when Mr Pathole travelled to the United States - his first trip overseas - to begin a master's degree in business analytics.

"He is super genuine. Like, way down-to-earth. He's humble," the 23-year-old told Agence France-Presse (AFP) beforehand. "The way he takes his time to respond to me... just shows."

Mr Musk is a prolific user of Twitter, often posting more than 30 times a day to his 103 million followers.

But it remains a mystery why the SpaceX and Tesla boss, with a net worth of US$266 billion (S$371 billion), maintains regular contact with the young Indian.

"To be very honest, I have no idea. I think he must be like, really intrigued by my questions," Mr Pathole told AFP from his parents' upper-middle-class home in the western city of Pune.

Mr Pathole's account is one of only a small handful that the billionaire frequently replies to - an average of once every two days, based on Mr Musk's public Twitter posts since the start of 2020.

The first time Mr Musk responded to him was in 2018 when Mr Pathole, then aged 19, pointed out a flaw in Tesla's automatic windshield wipers.

"Fixed in next release," Mr Musk replied, with Tesla addressing the issue in a subsequent software update.

Mr Pathole's mother and father celebrated by taking him out to dinner that night.

"I was blown away, to be very honest," he said. "I took multiple screenshots of it and just never wanted the day to end."

Their later private chats - daily at first - covered "busting myths" about Mr Musk's past and discussions about why colonising other planets is "essential", Mr Pathole said.

"I used to ask him dumb questions, silly questions. And he used to take his time to reply to me."

The time difference between the US and India has done little to hamper the four-year virtual friendship.

"I don't think he sleeps that often. Because he's on Twitter, like, the majority of the time," Mr Pathole said.

Mr Musk's candid, irreverent and often cryptic tweets have sparked wild stock and cryptocurrency price swings, inviting scrutiny by US regulators.

The billionaire investor is also locked in a high-stakes legal battle with Twitter over his effort to walk away from an agreement to buy the company, with the trial set to begin in October.

But Mr Pathole rejects suggestions that the billionaire acts with malice.

"I don't think that he's a troll," Mr Pathole said. "He's an unpredictable guy."

Recruited straight out of engineering college to work at Tata Consultancy Services, India's biggest IT firm, Mr Pathole said he was "infamous" for getting into trouble at school - a trait he said helps him better understand Mr Musk.

Having travelled to the US last week - bearing sweets for Mr Musk - he hopes to not only earn his degree at the University of Texas at Dallas but also gain work experience at a US company, including any of Mr Musk's.

"I want to get a job at Tesla on my own merit. It's not like I want any favours. It would be good if he could interview me," Mr Pathole says.

After their meeting, he tweeted a picture of the pair, which Mr Musk "liked".