How do u identify if a number is a power of 2?

Question

How do u identify if a number is a power of 2?

Answer 1

A number X is a power of 2 if X = 2^n

Then ln (X) = ln (2^n) = n ln (2)

n = ln (X) / ln (2)

If n = ln (X) / ln (2) is an integer, then X is an integer whole multiple of 2.

If n is not a whole number, X is still a power of 2, but not an integer power of 2; i.e.

6 = 2^2.5849625...

6 = 2 to the 2.5849625... power

Answer 2

its divisible by 2 too ..

Answer 3

Look at the units digit of the number.

A number which is the power of 2 will heve

either 0,1,4,5,6 or 9 at its units place.

But not vice versa.

Answer 4

The simplest way is to take the logarithm for base 2 for the number which you want to know whether it is a power of 2.

Regards,

Answer 5

Enter 1 on your hand held calculator. Multiply by 2. Repeat. You'll get 4, 8, 16, etc. If you go past your sample number but don't equal it, it's not a power of 2.