# 155

## 155 is an odd composite number composed of two prime numbers multiplied together.

What does the number 155 look like?

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

155 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 155:

### 5 × 31

See below for interesting mathematical facts about the number 155 from the Numbermatics database.

### Names of 155

• Cardinal: 155 can be written as One hundred fifty-five.

### Scientific notation

• Scientific notation: 1.55 × 102

### Factors of 155

• Number of distinct prime factors ω(n): 2
• Total number of prime factors Ω(n): 2
• Sum of prime factors: 36

### Divisors of 155

• Number of divisors d(n): 4
• Complete list of divisors:
• Sum of all divisors σ(n): 192
• Sum of proper divisors (its aliquot sum) s(n): 37
• 155 is a deficient number, because the sum of its proper divisors (37) is less than itself. Its deficiency is 118

### Bases of 155

• Binary: 100110112
• Base-36: 4B

### Squares and roots of 155

• 155 squared (1552) is 24025
• 155 cubed (1553) is 3723875
• The square root of 155 is 12.4498995979
• The cube root of 155 is 5.3716853549

### Scales and comparisons

How big is 155?
• 155 seconds is equal to 2 minutes, 35 seconds.
• To count from 1 to 155 would take you about seventeen 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 155 cubic inches would be around 0.4 feet tall.

### Recreational maths with 155

• 155 backwards is 551
• The number of decimal digits it has is: 3
• The sum of 155's digits is 11
• More coming soon!