# 1561

## 1,561 is an odd composite number composed of two prime numbers multiplied together.

What does the number 1561 look like?

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

1561 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 1561:

### 7 × 223

See below for interesting mathematical facts about the number 1561 from the Numbermatics database.

### Names of 1561

• Cardinal: 1561 can be written as One thousand, five hundred sixty-one.

### Scientific notation

• Scientific notation: 1.561 × 103

### Factors of 1561

• Number of distinct prime factors ω(n): 2
• Total number of prime factors Ω(n): 2
• Sum of prime factors: 230

### Divisors of 1561

• Number of divisors d(n): 4
• Complete list of divisors:
• Sum of all divisors σ(n): 1792
• Sum of proper divisors (its aliquot sum) s(n): 231
• 1561 is a deficient number, because the sum of its proper divisors (231) is less than itself. Its deficiency is 1330

### Bases of 1561

• Binary: 110000110012
• Base-36: 17D

### Squares and roots of 1561

• 1561 squared (15612) is 2436721
• 1561 cubed (15613) is 3803721481
• The square root of 1561 is 39.5094925303
• The cube root of 1561 is 11.6002576241

### Scales and comparisons

How big is 1561?
• 1,561 seconds is equal to 26 minutes, 1 second.
• To count from 1 to 1,561 would take you about twenty-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 1561 cubic inches would be around 1 feet tall.

### Recreational maths with 1561

• 1561 backwards is 1651
• The number of decimal digits it has is: 4
• The sum of 1561's digits is 13
• More coming soon!

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The information we have on file for 1561 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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