Apple’s donut-shaped headquarters in Cupertino, California has been valued at $4.17bn, according to a new assessment this week – making it one of the most expensive buildings in the world.

David Ginsborg, deputy assessor of Santa Clara county, where Cupertino is located, said that the unconventional 2.8m sq ft property was a challenge to evaluate.

“I mean, every bit of it is custom,” he said. The intricately designed ring – which incorporates treated glass, and specially designed tiles – is surrounded by pines from the Mojave Desert. “But at the end of the day, it’s an office building,” Ginsborg said. “And so we were able to put a number on it.”

The headquarters cost $5bn to construct. By contrast, the world’s tallest building – the Burj Kalifa in Dubai – cost $1.5bn. The Marina Bay Sands resort in Singapore cost about $5.5bn. Usually, the market value of a building is similar to the cost of its construction plus the land it occupies, said Santa Clara county assessor Larry Stone.

The company is required to pay about 1% in property tax, per California law. Based on the valuation by Santa Clara county, Apple will owe over $40m in property taxes each year in California.

But critics have argued that the amount – a tiny fraction of the company’s revenue – does not offset its contribution to the housing crisis and homelessness.

The largest chunk of it – about 25% – helps fund the local elementary school. An additional 15% funds the local fire fighting services. The city of Cupertino directly receives 6% for discretionary spending. As part of its Apple Park development agreement, the company paid $5.85m into an affordable housing fund. It also invested $75m to improve infrastructure and ease traffic in several nearby cities.

Moreover, Apple benefits from a tax-incentive deal with the city of Cupertino, which has given almost $70m in sales-tax collections back to the company over the past 20 years, Bloomberg reported.

Apple is the largest property taxpayer in the county, according to Stone. “And of course, they’re a major employer – so that’s another benefit to the county.”