The number 79401
79401 is a triangular number: 1 + 2 + … + 398 = 79401. Its prime factorisation is 3 × 7 × 19 × 199. Divisors (16): 1, 3, 7, 19, 21, 57, 133, 199, 399, 597, 1393, 3781, 4179, 11343, 26467, 79401.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 79401: a triangular number: 1 + 2 + … + 398 = 79401; a Harshad number: divisible by its digit sum 21.
- 2
79401 is composite. Its prime factorisation is
- 3
The divisors add up to 128000; without 79401 itself that is 48599, so 79401 is deficient (48599 is less than 79401). Euler's totient φ(79401) = 42768 numbers up to 79401 share no factor with it.
- 4
The digits of 79401 add up to 21, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 107 steps to reach 1.
LaTeX source of the formulas on this page
\[ 79401 = 3 \times 7 \times 19 \times 199 \]
79401 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 128000 |
| Euler totient φ(n) | 42768 |
| Square | 6304518801 |
| Cube | 500585097318201 |
| Square root | 281.781831 |
| Digit sum / digital root | 21 / 3 |
| Collatz steps to 1 | 107 |
| Scientific notation | 7.9401 × |
79401 in other forms
| Form | Value |
|---|---|
| In words | seventy-nine thousand four hundred and one |
| Binary (base 2) | 10011011000101001 |
| Octal (base 8) | 233051 |
| Hexadecimal (base 16) | 13629 |
| Base 3 | 11000220210 |
| As time | 79401 seconds = 22 h 3 min 21 s |
Is 79401 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 | Yes (79401 ÷ 3 = 26467) | 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 3) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (79401 ÷ 7 = 11343) | 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 3) | 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 3) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 79401 a prime number?
No. 79401 = 3 × 7 × 19 × 199, so it is divisible by 3.
What are the factors of 79401?
1, 3, 7, 19, 21, 57, 133, 199, 399, 597, 1393, 3781, 4179, 11343, 26467, 79401.
What is 79401 in binary?
10011011000101001 (hexadecimal 13629, octal 233051).
What is the square root of 79401?
About 281.7818.
Is 79401 divisible by 3?
Yes. Its digits add up to 21, a multiple of 3.
What is special about the number 79401?
79401 is a triangular number: 1 + 2 + … + 398 = 79401; a Harshad number: divisible by its digit sum 21.