You know that prime number, natural number, Armstrong number but do you know about Friedman number. Well if you don’t know about this magical number then this article for you. Friedman numbers are named after Erich Friedman, a now-retired mathematics professor at Stetson University, located in DeLand, Florida.

What is Friedman number?

According to Wikipedia, A Friedman number is an integer, which represented in a given numeral system, is the result of a non-trivial expression using all its own digits in combination with any of the four basic arithmetic operators (+, −, ×, ÷), additive inverses, parentheses, exponentiation, and concatenation.

In a simple explanation, it is number which can be achieve by applying arithmetic operators with using their own digits with any combination.

Example:

The expressions of the first few Friedman numbers are:

number	expression	number	expression	number	expression	number	expression
25	5²	127	2⁷−1	289	(8+9)²	688	8×86
121	11²	128	2⁸⁻¹	343	(3+4)³	736	3⁶+7
125	5¹⁺²	153	3×51	347	7³+4	1022	2¹⁰−2
126	6×21	216	6²⁺¹	625	5⁶⁻²	1024	(4−2)¹⁰

Before moving further with this number, do you also know about the Why 6174 is a magical number? You can check from below link:

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Well now we can see some more pictorial example of Friedman number.

What is Friedman number and program in Java — What is Friedman number? How to find it [Source Code]

Now most probably, you understand the concept of this number. Now lets move to the source code of find a number is Friedman number or not. Program is written in Java.