When you're filthy rich, it's hard to keep a firm grasp on reality. This is why Mike Tyson owns a pet tiger and Gwyneth Paltrow is trying to sell everyone gold-plated juicers for Christmas.

It makes sense, then, that a wealthy man from Thai Nguyen would spend nearly US$135,000 on one of Mobifone's prized “super SIM” phone numbers. According to VnExpress, Mobifone transferred ownership of the phone number – 0933 999 999 – at 5pm on November 2 in Hanoi, with its previous owner pocketing nearly VND3 billion in the transaction.

“I purchased this SIM from a wealthy real estate developer in Hanoi in 2013 for over VND1 billion,” Do Trong Hieu, former owner of the prized phone number and director of Me Linh Commercial Services, told VnExpress. “A man from Thai Nguyen just purchased it for personal use. It's a rare kind of phone number, as the number nine means everlasting and the number three means fortune. Thirty-nine is a symbol of wealth, so the person who buys it will receive lots of luck.”

The new owner of the phone number also confirmed its purchase, saying that he had previously used only Viettel numbers beginning with 097 and 098.

“I rarely resell a SIM I purchase for personal use, unless a more attractive SIM number comes along,” the new owner told VnExpress.

This is Mobifone's most expensive SIM sale of 2015, but you'll be pleased to learn that it's not the highest of all. In March, the chairman of Mai Linh Group transferred his own “super SIM” number – 09 89 999 999 – to a wealthy Saigon resident to the tune of nearly VND5 billion (US$225,000).