Bitcoin's Magic Number!
Bitcoin's Magic Number!

By Thalers-r | Crypto Curious | 23 May 2020

A magic number is a number at the beginning of (or near to beginning) a file that identifies type of a file. It is also called “magic bytes” and/or “file signatures”.  It is like a package of a candy bar.


You can think of package as a magic number. You know what is inside and it’s properties like how it tastes, smells, etc.

A magic number is a base 16 number (hexadecimal). It starts with “0x” which is not part of the number. “0x” is a prefix telling: “Oh hey the characters after me represent a number in base 16”.  We know that “a” is actually 11, “b” is 12 and so on. By the way if you have not read already here is an article about “hashes”. In that, I tried to explain number systems and hashes.

Let’s take a look at some examples of magic numbers, widely known and used file types.


D9 B4 BE F9 is the first element of a Bitcoin block. It may also start with F9 BE B4 D9 because of “byte ordering”, this is normal, it is the same thing. Some processors store left to right some right to left.

The Magic Number of Bitcoin is 4 bytes of data and it is at the beginning of every block in the Bitcoin blockchain since 2009.


Out of all the numbers why did Satoshi Nakamoto pick this particular number to represent the Bitcoin blocks?

Does it mean something special to Satoshi Nakamoto?

Is it a key to unlock a mystery?

Or is it a secret message?

When converted to text, Bitcoin’s Magic Number is not readable. As a decimal number (4190024921) it is a prime number which might be the only thing that stands out. Other than Bitcoin’s Magic Number being a prime number, it seems quite random. Maybe someday the mysterious creator sheds light on it.


Thank you for reading. I hope, you enjoyed it and/or it helped you somehow.

If you would like to read about Merkle Tree structure and why it is crucial for Bitcoin.Here is a link.

Have a nice day :)

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