[solidangle]

It could be, but it would be the size of a tennis ball. See https://news.ycombinator.com/item?id=28167058

[pitaj]

According to my calculations it would take more than 10^53 years to decay.

[scatters]

It won't even start to decay until space expands enough that it's warmer than the cosmological background, not that that's more than a rounding error to your calculation.