The number 5991
5991 is a composite number with 4 divisors. Its prime factorisation is 3 × 1997. Divisors (4): 1, 3, 1997, 5991.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 5991: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 3 × 1997, the product of two primes.
- 2
5991 is composite. Its prime factorisation is
- 3
The divisors add up to 7992; without 5991 itself that is 2001, so 5991 is deficient (2001 is less than 5991). Euler's totient φ(5991) = 3992 numbers up to 5991 share no factor with it.
- 4
The digits of 5991 add up to 24, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 93 steps to reach 1.
LaTeX source of the formulas on this page
\[ 5991 = 3 \times 1997 \]
5991 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 7992 |
| Euler totient φ(n) | 3992 |
| Square | 35892081 |
| Cube | 215029457271 |
| Square root | 77.401550 |
| Digit sum / digital root | 24 / 6 |
| Collatz steps to 1 | 93 |
| Scientific notation | 5.991 × |
5991 in other forms
| Form | Value |
|---|---|
| In words | five thousand nine hundred and ninety-one |
| Binary (base 2) | 1011101100111 |
| Octal (base 8) | 13547 |
| Hexadecimal (base 16) | 1767 |
| Base 3 | 22012220 |
| As time | 5991 seconds = 1 h 39 min 51 s |
Is 5991 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | No (remainder 1) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (5991 ÷ 3 = 1997) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 3) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 1) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 3) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 6) | A number is divisible by 7 if double the last digit and subtract it from the rest: the result is a multiple of 7. |
| 8 | No (remainder 7) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 6) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 1) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 7) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 3) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 5991 a prime number?
No. 5991 = 3 × 1997, so it is divisible by 3.
What are the factors of 5991?
1, 3, 1997, 5991.
What is 5991 in binary?
1011101100111 (hexadecimal 1767, octal 13547).
What is the square root of 5991?
About 77.4016.
Is 5991 divisible by 3?
Yes. Its digits add up to 24, a multiple of 3.
What is special about the number 5991?
5991 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 3 × 1997, the product of two primes.