The number 72401
72401 is a composite number with 4 divisors. Its prime factorisation is 7 × 10343. Divisors (4): 1, 7, 10343, 72401.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 72401: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 7 × 10343, the product of two primes.
- 2
72401 is composite. Its prime factorisation is
- 3
The divisors add up to 82752; without 72401 itself that is 10351, so 72401 is deficient (10351 is less than 72401). Euler's totient φ(72401) = 62052 numbers up to 72401 share no factor with it.
- 4
The digits of 72401 add up to 14, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 94 steps to reach 1.
LaTeX source of the formulas on this page
\[ 72401 = 7 \times 10343 \]
72401 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 82752 |
| Euler totient φ(n) | 62052 |
| Square | 5241904801 |
| Cube | 379519149497201 |
| Square root | 269.074339 |
| Digit sum / digital root | 14 / 5 |
| Collatz steps to 1 | 94 |
| Scientific notation | 7.2401 × |
72401 in other forms
| Form | Value |
|---|---|
| In words | seventy-two thousand four hundred and one |
| Binary (base 2) | 10001101011010001 |
| Octal (base 8) | 215321 |
| Hexadecimal (base 16) | 11AD1 |
| Base 3 | 10200022112 |
| As time | 72401 seconds = 20 h 6 min 41 s |
Is 72401 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 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 5) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (72401 ÷ 7 = 10343) | 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 5) | 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 10) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 72401 a prime number?
No. 72401 = 7 × 10343, so it is divisible by 7.
What are the factors of 72401?
1, 7, 10343, 72401.
What is 72401 in binary?
10001101011010001 (hexadecimal 11AD1, octal 215321).
What is the square root of 72401?
About 269.0743.
Is 72401 divisible by 3?
No. Its digits add up to 14, which is not a multiple of 3.
What is special about the number 72401?
72401 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 7 × 10343, the product of two primes.