Crypto Math Primality Test

Choose this endpoint when you need a deterministic, mathematically rigorous primality test — especially for cryptographic use cases where probabilistic answers are not acceptable. It handles numbers up to 1024 bits (far beyond JavaScript's native integers), accepts both decimal and hex input, and optionally locates neighboring primes, making it ideal for RSA key generation, cryptographic parameter selection, and number theory computations. Prefer it over general-purpose math APIs when BigInt support and deterministic correctness below 2^64 are required.

• Missing required parameter n returns an error
• Non-numeric or malformed input string causes parsing failure
• Numbers larger than 1024 bits are rejected as out of range
• neighbors=true on numbers larger than 512 bits may be unsupported or degraded
• Network timeout for very large inputs near the upper bit limit
• x402 payment failure if USDC balance is insufficient