The number 72170
72170 is a composite number with 16 divisors. Its prime factorisation is 2 × 5 × 7 × 1031. Divisors (16): 1, 2, 5, 7, 10, 14, 35, 70, 1031, 2062, 5155, 7217, 10310, 14434, 36085, 72170.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 72170: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
72170 is composite. Its prime factorisation is
- 3
The divisors add up to 148608; without 72170 itself that is 76438, so 72170 is abundant (76438 is more than 72170). Euler's totient φ(72170) = 24720 numbers up to 72170 share no factor with it.
- 4
The digits of 72170 add up to 17, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 143 steps to reach 1.
LaTeX source of the formulas on this page
\[ 72170 = 2 \times 5 \times 7 \times 1031 \]
72170 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 148608 |
| Euler totient φ(n) | 24720 |
| Square | 5208508900 |
| Cube | 375898087313000 |
| Square root | 268.644747 |
| Digit sum / digital root | 17 / 8 |
| Collatz steps to 1 | 143 |
| Scientific notation | 7.217 × |
72170 in other forms
| Form | Value |
|---|---|
| In words | seventy-two thousand one hundred and seventy |
| Binary (base 2) | 10001100111101010 |
| Octal (base 8) | 214752 |
| Hexadecimal (base 16) | 119EA |
| Base 3 | 10122222222 |
| As time | 72170 seconds = 20 h 2 min 50 s |
Is 72170 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (72170 ÷ 2 = 36085) | 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 2) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (72170 ÷ 5 = 14434) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 2) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (72170 ÷ 7 = 10310) | 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 2) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 8) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (72170 ÷ 10 = 7217) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 10) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 2) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 72170 a prime number?
No. 72170 = 2 × 5 × 7 × 1031, so it is divisible by 2.
What are the factors of 72170?
1, 2, 5, 7, 10, 14, 35, 70, 1031, 2062, 5155, 7217, 10310, 14434, 36085, 72170.
What is 72170 in binary?
10001100111101010 (hexadecimal 119EA, octal 214752).
What is the square root of 72170?
About 268.6447.
Is 72170 divisible by 3?
No. Its digits add up to 17, which is not a multiple of 3.
What is special about the number 72170?
72170 is a happy number: repeatedly adding the squares of its digits reaches 1.