Limits RegistryPUBLIC RECORD
Limits RegistryThe largest known factorial prime is 632760! - 1, with 3,395,992 digits, found by the PrimeGrid project in 2024. Factorial primes are far rarer than Mersenne-style primes because no fast special-purpose test exists for them.
The question, scope, and sources behind this Registry record.
The largest known factorial prime is 632760! - 1, with 3,395,992 digits, found by the PrimeGrid project in 2024. Factorial primes are far rarer than Mersenne-style primes because no fast special-purpose test exists for them.
The largest known prime of the form n! + 1 or n! - 1.
Change a parameter to stress-test whether a proposed result is still inside the published specification. This is an audit aid, not a proof checker.
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Current frontiers derived from accepted Claims.
An observed or demonstrated result; no opposing bound is implied.
The frontier is not sacred
Most progress starts with a disagreement that survives contact with evidence. If you can push the known lower bound up or pull the upper bound down, show us the work.
≥ when you have shown that at least this value is achievable.≤ when you have shown that anything above this value is impossible.No vibes. State the value, define the scope, and link the paper, proof, code, or reproduction that lets another person check it. Editors review every challenge before the public record changes.
Challenge this recordAssertions tied to evidence, attribution, and review.
The frontier as it changed over time.
Only accepted Claims matching the current specification contribute to the displayed bounds. Strict inequalities remain open; contradictory Claims require editorial review.
1 accepted Claim, with 1 linked evidence records.
Permanent ID limitsregistry.com/limits/LR-LARGEST-KNOWN-FACTORIAL-PRIME
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Limits Registry. LR-LARGEST-KNOWN-FACTORIAL-PRIME. Largest known factorial prime. 2026.