The number 7979
7979 is a composite number with 4 divisors. Its prime factorisation is 79 × 101. Divisors (4): 1, 79, 101, 7979.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 7979: a semiprime: 79 × 101, the product of two primes.
- 2
7979 is composite. Its prime factorisation is
- 3
The divisors add up to 8160; without 7979 itself that is 181, so 7979 is deficient (181 is less than 7979). Euler's totient φ(7979) = 7800 numbers up to 7979 share no factor with it.
- 4
The digits of 7979 add up to 32, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 52 steps to reach 1.
LaTeX source of the formulas on this page
\[ 7979 = 79 \times 101 \]
7979 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 8160 |
| Euler totient φ(n) | 7800 |
| Square | 63664441 |
| Cube | 507978574739 |
| Square root | 89.325248 |
| Digit sum / digital root | 32 / 5 |
| Collatz steps to 1 | 52 |
| Scientific notation | 7.979 × |
7979 in other forms
| Form | Value |
|---|---|
| In words | seven thousand nine hundred and seventy-nine |
| Binary (base 2) | 1111100101011 |
| Octal (base 8) | 17453 |
| Hexadecimal (base 16) | 1F2B |
| Base 3 | 101221112 |
| As time | 7979 seconds = 2 h 12 min 59 s |
Is 7979 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 3) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 4) | 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 | 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 3) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 5) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 9) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 4) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 11) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 7979 a prime number?
No. 7979 = 79 × 101, so it is divisible by 79.
What are the factors of 7979?
1, 79, 101, 7979.
What is 7979 in binary?
1111100101011 (hexadecimal 1F2B, octal 17453).
What is the square root of 7979?
About 89.3252.
Is 7979 divisible by 3?
No. Its digits add up to 32, which is not a multiple of 3.
What is special about the number 7979?
7979 is a semiprime: 79 × 101, the product of two primes.