Primecoin logo
PluralPrimecoin, primecoins
 0.001mXPM (millicoin)
 0.000001μXPM (microcoin)
 0.00000001Smallest unit
Official user(s)International
Issuing authorityNone, the primecoin peer-to-peer network regulates and distributes through consensus in protocol.[citation needed]
Date of introduction7 July 2013[1]
Inflation_rateLimited release, production rate before this limit re-evaluated with the production of every block (at a rate of approximately 1 block per minute) based on the difficulty with which primecoins are produced.[citation needed]

Primecoin (Abbreviation: XPM) is a cryptocurrency that implements a proof-of-work system that searches for chains of prime numbers.


Primecoin was launched in 2013 by Sunny King, who also founded Peercoin.[2][3]

Unlike other cryptocurrencies, which are mined using algorithms that solved mathematical problems with no extrinsic value, mining Primecoin involves producing chains of prime numbers (Cunningham and bi-twin chains). These are useful to scientists and mathematicians and meet the requirements for a proof of work system of being hard to compute but easy to verify and having an adjustable difficulty.[4][1][2][5][3][6]

Shortly after its launch, some trade journals reported that the rush of over 18,000 new users seeking to mine Primecoin overwhelmed providers of dedicated servers.[1][7]

Primecoin has a block time of one minute, changes difficulty every block, and has a block reward that is a function of the difficulty.[2][6]


  1. ^ a b c Clark, Jack (16 July 2013). "Virtual currency speculators shut down cloud". The Register. Retrieved 17 November 2018.
  2. ^ a b c Franco, Pedro (21 October 2018). Understanding Bitcoin: Cryptography, Engineering and Economics. Chichester, West Sussex, UK: John Wiley & Sons. pp. 175–76. ISBN 978-1-119-01914-5. Archived from the original on 17 November 2018.
  3. ^ a b Peck, Morgen E. (29 April 2014). "Bitcoin Vies with New Cryptocurrencies as Coin of the Cyber Realm". Scientific American. Retrieved 17 November 2018.
  4. ^ "Exploring Primecoin: An Alternative Cryptocurrency Project - Codemotion". Codemotion Magazine. 16 November 2020. Retrieved 12 July 2022.
  5. ^ Pirjan, Alexandru; Petrosanu, Dana-Mihaela; Huth, Mihnea; Negoita, Mihaela (2015). "Research issues regarding the Bitcoin and Alternative Coins digital currencies". Romanian-American University via Gale. Archived from the original on 17 November 2018. Retrieved 17 November 2018.
  6. ^ a b Gibbs, Samuel (28 November 2013). "Nine Bitcoin alternatives for future currency investments". The Guardian. Retrieved 17 November 2018.
  7. ^ Miller, Rich (17 December 2013). "Currency Miners Cause Spot Shortages of Dedicated Servers". Data Center Knowledge. Retrieved 18 December 2013.

Further reading