Home/Chain Registry/Block #6,784,907

Block #6,784,907

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 4/5/2026, 10:32:44 PM · Difficulty 10.9809 · 7,907 confirmations

2CC

Cunningham Chain of the Second Kind

A sequence where each prime is double the previous prime minus one.

Block Header

Block Hash

0d8ecd73b3ce18b828e9e49f3153f0bed8b3a5f52e79b2d41b144c4aa2a32d28

View on Chainz ↗

Height

#6,784,907

Difficulty

10.980851

Transactions

Size

192 B

Version

536870912

Bits

0afb190a

Nonce

1,552,327,720

Timestamp

4/5/2026, 10:32:44 PM

Confirmations

7,907

Merkle Root

1ef80d4b3fea0e8274a952a25cb63c475e00eb228bc516acd66cb8bcb1e99e5e

Transactions (1)

Coinbase1ef80d4b3fea0e…6cb8bcb1e99e5e

1 in → 1 out8.1790 XPM101 B

AMrLYUQN…jwjifxiz

Prime Chain Origin

This is the prime chain origin stored in the block header. It is a composite number (not prime itself) — it equals the first prime in the chain multiplied by a primorial. The origin anchors the entire chain to this specific block.

1.457 × 10⁹⁸(99-digit number)

14576856769571454084…29127890267351941120

Discovered Prime Numbers

p_k = 2^k × origin + 1

These are the actual prime numbers discovered by this block, computed using the verified Primecoin formula. Each number has been independently confirmed to pass the Fermat primality test. Use the FactorDB links to verify any number independently.

origin + 1

1.457 × 10⁹⁸(99-digit number)

14576856769571454084…29127890267351941121

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^1 × origin + 1

2.915 × 10⁹⁸(99-digit number)

29153713539142908168…58255780534703882241

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^2 × origin + 1

5.830 × 10⁹⁸(99-digit number)

58307427078285816336…16511561069407764481

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^3 × origin + 1

1.166 × 10⁹⁹(100-digit number)

11661485415657163267…33023122138815528961

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^4 × origin + 1

2.332 × 10⁹⁹(100-digit number)

23322970831314326534…66046244277631057921

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^5 × origin + 1

4.664 × 10⁹⁹(100-digit number)

46645941662628653068…32092488555262115841

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^6 × origin + 1

9.329 × 10⁹⁹(100-digit number)

93291883325257306137…64184977110524231681

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^7 × origin + 1

1.865 × 10¹⁰⁰(101-digit number)

18658376665051461227…28369954221048463361

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^8 × origin + 1

3.731 × 10¹⁰⁰(101-digit number)

37316753330102922455…56739908442096926721

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^9 × origin + 1

7.463 × 10¹⁰⁰(101-digit number)

74633506660205844910…13479816884193853441

Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 10 consecutive prime numbers forming a Cunningham Chain of the Second Kind. The prime chain origin — the large number shown above — anchors the chain and is divisible by a primorial (the product of small primes), cryptographically tying these prime numbers to this specific block.

View full Prime Chain Discovery page →

★★☆☆☆

Rarity

UncommonChain length 10

How Primecoin's Proof-of-Work Constructs These Primes

Primecoin stores a value called the prime chain origin in each block. The miner found a large integer such that when divided by a primorial (the product of small primes: 2 × 3 × 5 × 7 × …), the result is the first prime in the chain. The origin is deliberately divisible by this primorial — that divisibility is part of the proof.

Prime Chain Origin = First Prime × Primorial (2·3·5·7·11·…)

Source: Primecoin prime.cpp — CheckPrimeProofOfWork()

This is why the origin has many small prime factors — those factors are the primorial divisor. The chain then extends from the first prime using the 2CC formula:

2CC: p₁ (first prime), p₂ = 2p₁ − 1, p₃ = 2p₂ − 1, …

Verify on a Primecoin Node

Anyone running a Primecoin node can independently verify this block using the following RPC commands. Run these from the primecoin-cli command line or via the debug console in the Primecoin wallet.

1. Get block hash by height

getblockhash 6784907

Returns the block hash for a given block height. Use this to confirm the hash shown above matches the chain.

2. Get full block data

getblock 0d8ecd73b3ce18b828e9e49f3153f0bed8b3a5f52e79b2d41b144c4aa2a32d28

Returns the full block header including difficulty, prime chain origin, prime chain type, transaction IDs, and all other fields shown on this page.

How to run these commands: To verify this data independently, open a terminal on your own Primecoin node and run primecoin-cli <command>. Alternatively, open the Primecoin-Qt wallet, go to Help → Debug Window → Console, and type the command directly. The node must be fully synced to this block height for the commands to return results.

Cross-reference on Chainz Explorer

Chainz is an independent Primecoin block explorer. Compare this block's data to verify accuracy.

View Block #6,784,907 on Chainz ↗