# 78

## 78 is an even composite number composed of three prime numbers multiplied together.

What does the number 78 look like?

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

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

## Prime factorization of 78:

### 2 × 3 × 13

See below for interesting mathematical facts about the number 78 from the Numbermatics database.

### Names of 78

• Cardinal: 78 can be written as Seventy-eight.

### Scientific notation

• Scientific notation: 7.8 × 101

### Factors of 78

• Number of distinct prime factors ω(n): 3
• Total number of prime factors Ω(n): 3
• Sum of prime factors: 18

### Divisors of 78

• Number of divisors d(n): 8
• Complete list of divisors:
• Sum of all divisors σ(n): 168
• Sum of proper divisors (its aliquot sum) s(n): 90
• 78 is an abundant number, because the sum of its proper divisors (90) is greater than itself. Its abundance is 12

### Bases of 78

• Binary: 10011102
• Base-36: 26

### Squares and roots of 78

• 78 squared (782) is 6084
• 78 cubed (783) is 474552
• The square root of 78 is 8.8317608663
• The cube root of 78 is 4.2726586817

### Scales and comparisons

How big is 78?
• 78 seconds is equal to 1 minute, 18 seconds.
• To count from 1 to 78 would take you about thirty-nine seconds.

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 78 cubic inches would be around 0.4 feet tall.

### Recreational maths with 78

• 78 backwards is 87
• The number of decimal digits it has is: 2
• The sum of 78's digits is 15
• More coming soon!