Fourth power

In arithmetic and algebra, the fourth power of a number is the result of multiplying four instances of together:.
Fourth powers are also formed by multiplying a number by its cube. Furthermore, they are squares of squares.
Some people refer to as n tesseracted, hypercubed, zenzizenzic, biquadrate or supercubed instead of "to the power of 4".
The sequence of fourth powers of integers, known as biquadrates or tesseractic numbers, is:

Properties

The last digit of a fourth power in decimal can only be 0, 1, 5, or 6.
In hexadecimal the last nonzero digit of a fourth power is always 1.
Every positive integer can be expressed as the sum of at most 19 fourth powers; every integer larger than 13792 can be expressed as the sum of at most 16 fourth powers.
Fermat knew that a fourth power cannot be the sum of two other fourth powers. Euler conjectured that a fourth power cannot be written as the sum of three fourth powers, but 200 years later, in 1986, this was disproven by Elkies with:
Elkies showed that there are infinitely many other counterexamples for exponent four, some of which are:
Fourth-degree equations, which contain a fourth degree polynomial are, by the Abel–Ruffini theorem, the highest degree equations having a general solution using radicals.