# 21521

## 21,521 is a prime number. Like all primes greater than two, it is odd and has no factors apart from itself and one.

What does the number 21521 look like?

As a prime, it is not composed of any other numbers and has no internal structure.

21521 is a prime number. Like all primes (except two), it is an odd number.

## Prime factorization of 21521:

### 21521

See below for interesting mathematical facts about the number 21521 from the Numbermatics database.

### Names of 21521

• Cardinal: 21521 can be written as Twenty-one thousand, five hundred twenty-one.

### Scientific notation

• Scientific notation: 2.1521 × 104

### Factors of 21521

• Number of distinct prime factors ω(n): 1
• Total number of prime factors Ω(n): 1
• Sum of prime factors: 21521

### Divisors of 21521

• Number of divisors d(n): 2
• Complete list of divisors:
• Sum of all divisors σ(n): 21522
• Sum of proper divisors (its aliquot sum) s(n): 1
• 21521 is a deficient number, because the sum of its proper divisors (1) is less than itself. Its deficiency is 21520

### Bases of 21521

• Binary: 1010100000100012
• Base-36: GLT

### Squares and roots of 21521

• 21521 squared (215212) is 463153441
• 21521 cubed (215213) is 9967525203761
• The square root of 21521 is 146.7003749143
• The cube root of 21521 is 27.8155391621

### Scales and comparisons

How big is 21521?
• 21,521 seconds is equal to 5 hours, 58 minutes, 41 seconds.
• To count from 1 to 21,521 would take you about five hours.

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 21521 cubic inches would be around 2.3 feet tall.

### Recreational maths with 21521

• 21521 backwards is 12512
• 21521 is a twin prime! Its twin is 21523
• The number of decimal digits it has is: 5
• The sum of 21521's digits is 11
• More coming soon!