If you have a property in an object that only needs to be computed once, consider using `cached_property`

to store the result and serve for future function calls.

```
import functools
class Number:
def __init__(self, n):
self.n = n
@functools.cached_property
def is_prime(self):
return all(self.n % i for i in range(2, self.n))
```

Let’s test it with the Mersenne prime `524287`

.

```
n = Number(524287)
n.is_prime
```

After maybe 1-2 seconds of thinking you should get `True.`

Run it again and the result will be instantaneous!