The number 29981
29981 is a composite number with 4 divisors. Its prime factorisation is 7 × 4283. Divisors (4): 1, 7, 4283, 29981.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 29981: a semiprime: 7 × 4283, the product of two primes.
- 2
29981 is composite. Its prime factorisation is
- 3
The divisors add up to 34272; without 29981 itself that is 4291, so 29981 is deficient (4291 is less than 29981). Euler's totient φ(29981) = 25692 numbers up to 29981 share no factor with it.
- 4
The digits of 29981 add up to 29, and repeating that until one digit is left gives the digital root 2. The Collatz sequence (halve if even, else 3n+1) takes 72 steps to reach 1.
LaTeX source of the formulas on this page
\[ 29981 = 7 \times 4283 \]
29981 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 34272 |
| Euler totient φ(n) | 25692 |
| Square | 898860361 |
| Cube | 26948732483141 |
| Square root | 173.150224 |
| Digit sum / digital root | 29 / 2 |
| Collatz steps to 1 | 72 |
| Scientific notation | 2.9981 × |
29981 in other forms
| Form | Value |
|---|---|
| In words | twenty-nine thousand nine hundred and eighty-one |
| Binary (base 2) | 111010100011101 |
| Octal (base 8) | 72435 |
| Hexadecimal (base 16) | 751D |
| Base 3 | 1112010102 |
| As time | 29981 seconds = 8 h 19 min 41 s |
Is 29981 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 | No (remainder 2) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 1) | 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 5) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (29981 ÷ 7 = 4283) | 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 5) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 2) | 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 6) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 29981 a prime number?
No. 29981 = 7 × 4283, so it is divisible by 7.
What are the factors of 29981?
1, 7, 4283, 29981.
What is 29981 in binary?
111010100011101 (hexadecimal 751D, octal 72435).
What is the square root of 29981?
About 173.1502.
Is 29981 divisible by 3?
No. Its digits add up to 29, which is not a multiple of 3.
What is special about the number 29981?
29981 is a semiprime: 7 × 4283, the product of two primes.