The first number is off by an order of magnitude or two, and your napkin math estimate is higher than humanity's entire power production. Are you a human?
Ok let's see, 20 Watts is 20 joules per second. Einstein was alive for about 75 years, so that's 75x365x24x60x60 seconds by 20 Joules per second which is 47,304,000,000 Joules.
So you are correct, I dropped an order of magnitude.
Based on the numbers here: https://www.businessenergyuk.com/knowledge-hub/chatgpt-energ...
ChatGPT gets through 39.98 million kWh per day, or 1.4 x 10e14 Joules per day, about 1.6 x 10e9 Joules per second.
47,304,000,000 / 1,665,000,000 is about 28.4 seconds.
So you're right on two counts, I'm off by an order of magnitude and an erroneous milli prefix. Napkin maths huh.
I think the original point I was trying to make stands though.