# 721

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

What does the number 721 look like?

This visualization shows the relationship between its 2 prime factors (large circles) and 4 divisors.

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

## Prime factorization of 721:

### 7 × 103

See below for interesting mathematical facts about the number 721 from the Numbermatics database.

### Names of 721

• Cardinal: 721 can be written as Seven hundred twenty-one.

### Scientific notation

• Scientific notation: 7.21 × 102

### Factors of 721

• Number of distinct prime factors ω(n): 2
• Total number of prime factors Ω(n): 2
• Sum of prime factors: 110

### Divisors of 721

• Number of divisors d(n): 4
• Complete list of divisors:
• Sum of all divisors σ(n): 832
• Sum of proper divisors (its aliquot sum) s(n): 111
• 721 is a deficient number, because the sum of its proper divisors (111) is less than itself. Its deficiency is 610

### Bases of 721

• Binary: 10110100012
• Base-36: K1

### Squares and roots of 721

• 721 squared (7212) is 519841
• 721 cubed (7213) is 374805361
• The square root of 721 is 26.8514431639
• The cube root of 721 is 8.9669570223

### Scales and comparisons

How big is 721?
• 721 seconds is equal to 12 minutes, 1 second.
• To count from 1 to 721 would take you about six 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 721 cubic inches would be around 0.7 feet tall.

### Recreational maths with 721

• 721 backwards is 127
• The number of decimal digits it has is: 3
• The sum of 721's digits is 10
• More coming soon!

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"Number 721 - Facts about the integer". Numbermatics.com. 2022. Web. 3 July 2022.

APA style:
Numbermatics. (2022). Number 721 - Facts about the integer. Retrieved 3 July 2022, from https://numbermatics.com/n/721/

Chicago style:
Numbermatics. 2022. "Number 721 - Facts about the integer". https://numbermatics.com/n/721/

The information we have on file for 721 includes mathematical data and numerical statistics calculated using standard algorithms and methods. We are adding more all the time. If there are any features you would like to see, please contact us. Information provided for educational use, intellectual curiosity and fun!

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