# 400

## 400 is an even composite number composed of two prime numbers multiplied together.

What does the number 400 look like?

This visualization shows the relationship between its 2 prime factors (large circles) and 15 divisors.

400 is an even composite number. It is composed of two distinct prime numbers multiplied together. It has a total of fifteen divisors.

## Prime factorization of 400:

### 24 × 52

(2 × 2 × 2 × 2 × 5 × 5)

See below for interesting mathematical facts about the number 400 from the Numbermatics database.

### Names of 400

• Cardinal: 400 can be written as Four hundred.

### Scientific notation

• Scientific notation: 4 × 102

### Factors of 400

• Number of distinct prime factors ω(n): 2
• Total number of prime factors Ω(n): 6
• Sum of prime factors: 7

### Divisors of 400

• Number of divisors d(n): 15
• Complete list of divisors:
• Sum of all divisors σ(n): 961
• Sum of proper divisors (its aliquot sum) s(n): 561
• 400 is an abundant number, because the sum of its proper divisors (561) is greater than itself. Its abundance is 161

### Bases of 400

• Binary: 1100100002
• Base-36: B4

### Squares and roots of 400

• 400 squared (4002) is 160000
• 400 cubed (4003) is 64000000
• 400 is a perfect square number. Its square root is 20
• The cube root of 400 is 7.3680629971

### Scales and comparisons

How big is 400?
• 400 seconds is equal to 6 minutes, 40 seconds.
• To count from 1 to 400 would take you about three minutes.

This is a very rough estimate, based on a speaking rate of half a second every third order of magnitude. If you speak quickly, you could probably say any randomly-chosen number between one and a thousand in around half a second. Very big numbers obviously take longer to say, so we add half a second for every extra x1000. (We do not count involuntary pauses, bathroom breaks or the necessity of sleep in our calculation!)

• A cube with a volume of 400 cubic inches would be around 0.6 feet tall.

### Recreational maths with 400

• 400 backwards is 004
• 400 is a Harshad number.
• The number of decimal digits it has is: 3
• The sum of 400's digits is 4
• More coming soon!