Is 400 a prime number?

No, 400 is composite. It is divisible by 2, 4, 5, 8, 10, 16, 20, 25, 40, 50, 80, 100 and 200.

Factors of 400

Q: What is the prime factorization of 400?

400 = 2 × 2 × 2 × 2 × 5 × 5.

The factors of 400 are 1, 2, 4, 5, 8, 10, 16, 20, 25, 40, 50, 80, 100, 200 and 400. That is 15 factors in total.

A factor of 400 is a whole number that divides 400 exactly, with no remainder. 400 is a composite number because it has factors other than 1 and itself.

Factor pairs of 400

Two numbers that multiply to give 400:

1 × 400 = 400
2 × 200 = 400
4 × 100 = 400
5 × 80 = 400
8 × 50 = 400
10 × 40 = 400
16 × 25 = 400
20 × 20 = 400

Prime factorization of 400

400 = 2 × 2 × 2 × 2 × 5 × 5 = 2⁴ × 5². The prime factors of 400 are 2 and 5.

Quick facts about 400

Is 400 prime? No.
Even or odd: even.
Sum of its factors: 1 + 2 + 4 + 5 + 8 + 10 + 16 + 20 + 25 + 40 + 50 + 80 + 100 + 200 + 400 = 961.
400 is a perfect square (20 × 20), so it has an odd number of factors.

Factors of nearby numbers

Number	Factors
256	1, 2, 4, 8, 16, 32, 64, 128, 256
300	18 factors
320	14 factors
360	24 factors
500	1, 2, 4, 5, 10, 20, 25, 50, 100, 125, 250, 500
600	24 factors
720	30 factors
1000	16 factors

More about 400: 400 squared · square root of 400 · 400 in binary · 400 in Roman numerals.

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