The number 31621
31621 is a composite number with 4 divisors. Its prime factorisation is 103 × 307. Divisors (4): 1, 103, 307, 31621.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 31621: a semiprime: 103 × 307, the product of two primes.
- 2
31621 is composite. Its prime factorisation is
- 3
The divisors add up to 32032; without 31621 itself that is 411, so 31621 is deficient (411 is less than 31621). Euler's totient φ(31621) = 31212 numbers up to 31621 share no factor with it.
- 4
The digits of 31621 add up to 13, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 191 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31621 = 103 \times 307 \]
31621 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 32032 |
| Euler totient φ(n) | 31212 |
| Square | 999887641 |
| Cube | 31617447096061 |
| Square root | 177.822946 |
| Digit sum / digital root | 13 / 4 |
| Collatz steps to 1 | 191 |
| Scientific notation | 3.1621 × |
31621 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand six hundred and twenty-one |
| Binary (base 2) | 111101110000101 |
| Octal (base 8) | 75605 |
| Hexadecimal (base 16) | 7B85 |
| Base 3 | 1121101011 |
| As time | 31621 seconds = 8 h 47 min 1 s |
Is 31621 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 1) | 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 1) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 2) | 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 4) | 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 1) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 31621 a prime number?
No. 31621 = 103 × 307, so it is divisible by 103.
What are the factors of 31621?
1, 103, 307, 31621.
What is 31621 in binary?
111101110000101 (hexadecimal 7B85, octal 75605).
What is the square root of 31621?
About 177.8229.
Is 31621 divisible by 3?
No. Its digits add up to 13, which is not a multiple of 3.
What is special about the number 31621?
31621 is a semiprime: 103 × 307, the product of two primes.