The number 1531
1531 is the 242nd prime number. Its only divisors are 1 and 1531.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 1531: the 242nd prime number.
- 2
1531 is prime, so its only factors are 1 and 1531. It is the 242nd prime; the next prime is 1543 and the one before is 1523.
- 3
The divisors add up to 1532; without 1531 itself that is 1, so 1531 is deficient (1 is less than 1531). Euler's totient φ(1531) = 1530 numbers up to 1531 share no factor with it.
- 4
The digits of 1531 add up to 10, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 60 steps to reach 1.
1531 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 1532 |
| Euler totient φ(n) | 1530 |
| Square | 2343961 |
| Cube | 3588604291 |
| Square root | 39.127995 |
| Digit sum / digital root | 10 / 1 |
| Collatz steps to 1 | 60 |
| Scientific notation | 1.531 × |
1531 in other forms
| Form | Value |
|---|---|
| In words | one thousand five hundred and thirty-one |
| Roman numerals | MDXXXI |
| Binary (base 2) | 10111111011 |
| Octal (base 8) | 2773 |
| Hexadecimal (base 16) | 5FB |
| Base 3 | 2002201 |
| As time | 1531 seconds = 25 min 31 s |
Is 1531 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 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 1) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 5) | 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 3) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 1) | 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 2) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 7) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 1531 a prime number?
Yes. 1531 is divisible only by 1 and itself.
What are the factors of 1531?
1, 1531.
What is 1531 in binary?
10111111011 (hexadecimal 5FB, octal 2773).
What is the square root of 1531?
About 39.1280.
What is 1531 in Roman numerals?
MDXXXI.
Is 1531 divisible by 3?
No. Its digits add up to 10, which is not a multiple of 3.
What is special about the number 1531?
1531 is the 242nd prime number.