# 191

## 191 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 191 look like?

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

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

## Prime factorization of 191:

### 191

See below for interesting mathematical facts about the number 191 from the Numbermatics database.

### Names of 191

• Cardinal: 191 can be written as One hundred ninety-one.

### Scientific notation

• Scientific notation: 1.91 × 102

### Factors of 191

• Number of distinct prime factors ω(n): 1
• Total number of prime factors Ω(n): 1
• Sum of prime factors: 191

### Divisors of 191

• Number of divisors d(n): 2
• Complete list of divisors:
• Sum of all divisors σ(n): 192
• Sum of proper divisors (its aliquot sum) s(n): 1
• 191 is a deficient number, because the sum of its proper divisors (1) is less than itself. Its deficiency is 190

### Bases of 191

• Binary: 101111112
• Base-36: 5B

### Squares and roots of 191

• 191 squared (1912) is 36481
• 191 cubed (1913) is 6967871
• The square root of 191 is 13.8202749611
• The cube root of 191 is 5.7589652205

### Scales and comparisons

How big is 191?
• 191 seconds is equal to 3 minutes, 11 seconds.
• To count from 1 to 191 would take you about thirty-five 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 191 cubic inches would be around 0.5 feet tall.

### Recreational maths with 191

• 191 is the same when its digits are reversed! That makes it a palindromic prime number.
• 191 is a twin prime! Its twin is 193
• The number of decimal digits it has is: 3
• The sum of 191's digits is 11
• More coming soon!