The number 61987
61987 is the 6231st prime number. Its only divisors are 1 and 61987.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 61987: the 6231st prime number.
- 2
61987 is prime, so its only factors are 1 and 61987. It is the 6231st prime; the next prime is 61991 and the one before is 61981.
- 3
The divisors add up to 61988; without 61987 itself that is 1, so 61987 is deficient (1 is less than 61987). Euler's totient φ(61987) = 61986 numbers up to 61987 share no factor with it.
- 4
The digits of 61987 add up to 31, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 55 steps to reach 1.
61987 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 61988 |
| Euler totient φ(n) | 61986 |
| Square | 3842388169 |
| Cube | 238178115431803 |
| Square root | 248.971886 |
| Digit sum / digital root | 31 / 4 |
| Collatz steps to 1 | 55 |
| Scientific notation | 6.1987 × |
61987 in other forms
| Form | Value |
|---|---|
| In words | sixty-one thousand nine hundred and eighty-seven |
| Binary (base 2) | 1111001000100011 |
| Octal (base 8) | 171043 |
| Hexadecimal (base 16) | F223 |
| Base 3 | 10011000211 |
| As time | 61987 seconds = 17 h 13 min 7 s |
Is 61987 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 2) | 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 3) | 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 7) | 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 61987 a prime number?
Yes. 61987 is divisible only by 1 and itself.
What are the factors of 61987?
1, 61987.
What is 61987 in binary?
1111001000100011 (hexadecimal F223, octal 171043).
What is the square root of 61987?
About 248.9719.
Is 61987 divisible by 3?
No. Its digits add up to 31, which is not a multiple of 3.
What is special about the number 61987?
61987 is the 6231st prime number.