# 1821

## 1,821 is an odd composite number composed of two prime numbers multiplied together.

What does the number 1821 look like?

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

1821 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 1821:

### 3 × 607

See below for interesting mathematical facts about the number 1821 from the Numbermatics database.

### Names of 1821

• Cardinal: 1821 can be written as One thousand, eight hundred twenty-one.

### Scientific notation

• Scientific notation: 1.821 × 103

### Factors of 1821

• Number of distinct prime factors ω(n): 2
• Total number of prime factors Ω(n): 2
• Sum of prime factors: 610

### Divisors of 1821

• Number of divisors d(n): 4
• Complete list of divisors:
• Sum of all divisors σ(n): 2432
• Sum of proper divisors (its aliquot sum) s(n): 611
• 1821 is a deficient number, because the sum of its proper divisors (611) is less than itself. Its deficiency is 1210

### Bases of 1821

• Binary: 111000111012
• Base-36: 1EL

### Squares and roots of 1821

• 1821 squared (18212) is 3316041
• 1821 cubed (18213) is 6038510661
• The square root of 1821 is 42.6731765871
• The cube root of 1821 is 12.2115272221

### Scales and comparisons

How big is 1821?
• 1,821 seconds is equal to 30 minutes, 21 seconds.
• To count from 1 to 1,821 would take you about thirty 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 1821 cubic inches would be around 1 feet tall.

### Recreational maths with 1821

• 1821 backwards is 1281
• The number of decimal digits it has is: 4
• The sum of 1821's digits is 12
• More coming soon!