# 1645

## 1,645 is an odd composite number composed of three prime numbers multiplied together.

What does the number 1645 look like?

This visualization shows the relationship between its 3 prime factors (large circles) and 8 divisors.

1645 is an odd composite number. It is composed of three distinct prime numbers multiplied together. It has a total of eight divisors.

## Prime factorization of 1645:

### 5 × 7 × 47

See below for interesting mathematical facts about the number 1645 from the Numbermatics database.

### Names of 1645

• Cardinal: 1645 can be written as One thousand, six hundred forty-five.

### Scientific notation

• Scientific notation: 1.645 × 103

### Factors of 1645

• Number of distinct prime factors ω(n): 3
• Total number of prime factors Ω(n): 3
• Sum of prime factors: 59

### Divisors of 1645

• Number of divisors d(n): 8
• Complete list of divisors:
• Sum of all divisors σ(n): 2304
• Sum of proper divisors (its aliquot sum) s(n): 659
• 1645 is a deficient number, because the sum of its proper divisors (659) is less than itself. Its deficiency is 986

### Bases of 1645

• Binary: 110011011012
• Base-36: 19P

### Squares and roots of 1645

• 1645 squared (16452) is 2706025
• 1645 cubed (16453) is 4451411125
• The square root of 1645 is 40.5585995813
• The cube root of 1645 is 11.8047094101

### Scales and comparisons

How big is 1645?
• 1,645 seconds is equal to 27 minutes, 25 seconds.
• To count from 1 to 1,645 would take you about twenty-seven 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 1645 cubic inches would be around 1 feet tall.

### Recreational maths with 1645

• 1645 backwards is 5461
• The number of decimal digits it has is: 4
• The sum of 1645's digits is 16
• More coming soon!