# 261

## 261 is an odd composite number composed of two prime numbers multiplied together.

What does the number 261 look like?

This visualization shows the relationship between its 2 prime factors (large circles) and 6 divisors.

261 is an odd composite number. It is composed of two distinct prime numbers multiplied together. It has a total of six divisors.

## Prime factorization of 261:

### 32 × 29

(3 × 3 × 29)

See below for interesting mathematical facts about the number 261 from the Numbermatics database.

### Names of 261

• Cardinal: 261 can be written as Two hundred sixty-one.

### Scientific notation

• Scientific notation: 2.61 × 102

### Factors of 261

• Number of distinct prime factors ω(n): 2
• Total number of prime factors Ω(n): 3
• Sum of prime factors: 32

### Divisors of 261

• Number of divisors d(n): 6
• Complete list of divisors:
• Sum of all divisors σ(n): 390
• Sum of proper divisors (its aliquot sum) s(n): 129
• 261 is a deficient number, because the sum of its proper divisors (129) is less than itself. Its deficiency is 132

### Bases of 261

• Binary: 1000001012
• Base-36: 79

### Squares and roots of 261

• 261 squared (2612) is 68121
• 261 cubed (2613) is 17779581
• The square root of 261 is 16.1554944211
• The cube root of 261 is 6.3906765287

### Scales and comparisons

How big is 261?
• 261 seconds is equal to 4 minutes, 21 seconds.
• To count from 1 to 261 would take you about two 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 261 cubic inches would be around 0.5 feet tall.

### Recreational maths with 261

• 261 backwards is 162
• 261 is a Harshad number.
• The number of decimal digits it has is: 3
• The sum of 261's digits is 9
• More coming soon!