Is 256 a prime number?

No, 256 is composite. It is divisible by 2, 4, 8, 16, 32, 64 and 128.

Factors of 256

Q: What is the prime factorization of 256?

256 = 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2.

The factors of 256 are 1, 2, 4, 8, 16, 32, 64, 128 and 256. That is 9 factors in total.

A factor of 256 is a whole number that divides 256 exactly, with no remainder. 256 is a composite number because it has factors other than 1 and itself.

Factor pairs of 256

Two numbers that multiply to give 256:

1 × 256 = 256
2 × 128 = 256
4 × 64 = 256
8 × 32 = 256
16 × 16 = 256

Prime factorization of 256

256 = 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2 = 2⁸. The prime factors of 256 are 2.

Quick facts about 256

Is 256 prime? No.
Even or odd: even.
Sum of its factors: 1 + 2 + 4 + 8 + 16 + 32 + 64 + 128 + 256 = 511.
256 is a perfect square (16 × 16), so it has an odd number of factors.

Factors of nearby numbers

Number	Factors
200	1, 2, 4, 5, 8, 10, 20, 25, 40, 50, 100, 200
225	1, 3, 5, 9, 15, 25, 45, 75, 225
240	20 factors
250	1, 2, 5, 10, 25, 50, 125, 250
300	18 factors
320	14 factors
360	24 factors
400	15 factors

More about 256: square root of 256 · 256 in binary.

Another number? Try the prime number checker, the GCF and LCM calculator or see all factor lists.