//! Integer algorithms, grouped by family.
//!
//! - [`primes`] — primality testing, sieves, factorization.
//! - [`arith`] — GCD/LCM, modular exponentiation, modular inverse, CRT,
//! Euler's totient.
//! - [`properties`] — divisor-based predicates and the general perfect-power
//! detector.
//! - [`sequences`] — classical sequences (factorial, Fibonacci, triangular)
//! implemented iteratively with overflow checks.