The number 72390
72390 is a triangular number: 1 + 2 + … + 380 = 72390. Its prime factorisation is 2 × 3 × 5 × 19 × 127. Divisors (32): 1, 2, 3, 5, 6, 10, 15, 19, 30, 38, 57, 95, 114, 127, 190, 254 … 72390.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 72390: a triangular number: 1 + 2 + … + 380 = 72390.
- 2
72390 is composite. Its prime factorisation is
- 3
The divisors add up to 184320; without 72390 itself that is 111930, so 72390 is abundant (111930 is more than 72390). Euler's totient φ(72390) = 18144 numbers up to 72390 share no factor with it.
- 4
The digits of 72390 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 50 steps to reach 1.
LaTeX source of the formulas on this page
\[ 72390 = 2 \times 3 \times 5 \times 19 \times 127 \]
72390 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 32 |
| Sum of divisors | 184320 |
| Euler totient φ(n) | 18144 |
| Square | 5240312100 |
| Cube | 379346192919000 |
| Square root | 269.053898 |
| Digit sum / digital root | 21 / 3 |
| Collatz steps to 1 | 50 |
| Scientific notation | 7.239 × |
72390 in other forms
| Form | Value |
|---|---|
| In words | seventy-two thousand three hundred and ninety |
| Binary (base 2) | 10001101011000110 |
| Octal (base 8) | 215306 |
| Hexadecimal (base 16) | 11AC6 |
| Base 3 | 10200022010 |
| As time | 72390 seconds = 20 h 6 min 30 s |
Is 72390 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (72390 ÷ 2 = 36195) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (72390 ÷ 3 = 24130) | 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 (72390 ÷ 5 = 14478) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (72390 ÷ 6 = 12065) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 3) | 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 6) | 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 | Yes (72390 ÷ 10 = 7239) | 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 6) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 72390 a prime number?
No. 72390 = 2 × 3 × 5 × 19 × 127, so it is divisible by 2.
What are the factors of 72390?
1, 2, 3, 5, 6, 10, 15, 19, 30, 38, 57, 95, 114, 127, 190, 254, 285, 381, 570, 635, 762, 1270, 1905, 2413, 3810, 4826, 7239, 12065, 14478, 24130, 36195, 72390.
What is 72390 in binary?
10001101011000110 (hexadecimal 11AC6, octal 215306).
What is the square root of 72390?
About 269.0539.
Is 72390 divisible by 3?
Yes. Its digits add up to 21, a multiple of 3.
What is special about the number 72390?
72390 is a triangular number: 1 + 2 + … + 380 = 72390.