Eratosthenes sieve
Eratosthenes sieve of a given length up to 10 quadrillion. Over 100 million we use segmented sieve.
For advanced sieves, see eratostenes on GitHub.
Total of primes smaller or equal than 2 is 1, it took 1 μs. Used eratosthenes sieve.
Last one prime of the sieve:
2