Landon Curt Noll writes about the FNV hash, the calc arbitrary-precision calculator, expert C programming and large primes.
HN commenters point to it for the FNV hash page and the calc command-line calculator, which they suggest as a stronger alternative to bc.
> the time taken to compute the additional hash functions outweighs any gains in performance.
Sounds like you're using the wrong hash functions.
Are you using secure cryptographic hash functions perchance? (such as MD5, SHA, etc) Because they're not intended for use in data structures.
Most data structure algorithms just require a hash function with good avalanche behaviour and a statistically even bit dispersion. The FNV hash will do this for you with just a MUL and a XOR per byte, which is (rough guess) at least 100 times faster than SHA. FNV hash (http://www.isthe.com/chongo/tech/comp/fnv/) it's super-effective!
An alternative that isn't discussed in the Why not use ...? section is calc:
http://www.isthe.com/chongo/tech/comp/calc
It is very powerful, has history, shows previous calculations, and it's pretty darn quick too.
Of course, there are plenty more calculators, powerful too. I only mention calc because it bothers me that the name of this new project collides with it, without really providing anything useful beyond having been written in a fashionable language.
The hash is FNV-1a, which should be faster that what you usually get in your standard library. It's also relatively easy to implement with constexpr so that you get those nice compile time hashes.
http://www.isthe.com/chongo/tech/comp/fnv/
If you're looking for something more advanced while still at the command prompt, check out "calc":
http://isthe.com/chongo/tech/comp/calc/
On Fedora:
sudo dnf install calc ; alias bc=calc
It might be worth mentioning popular functions like FNV (http://isthe.com/chongo/tech/comp/fnv/) MurmurHash (https://github.com/aappleby/smhasher) and SipHash (https://131002.net/siphash/).
If for whatever reason you want to download the number, there are a couple of links here:
http://www.isthe.com/chongo/tech/math/digit/m57885161/prime-c.html#middle