The number 745
745 is a composite number with 4 divisors. Its prime factorisation is 5 × 149. Divisors (4): 1, 5, 149, 745.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 745: a semiprime: 5 × 149, the product of two primes.
- 2
745 is composite. Its prime factorisation is
- 3
The divisors add up to 900; without 745 itself that is 155, so 745 is deficient (155 is less than 745). Euler's totient φ(745) = 592 numbers up to 745 share no factor with it.
- 4
The digits of 745 add up to 16, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 90 steps to reach 1.
LaTeX source of the formulas on this page
\[ 745 = 5 \times 149 \]
745 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 900 |
| Euler totient φ(n) | 592 |
| Square | 555025 |
| Cube | 413493625 |
| Square root | 27.294688 |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 90 |
| Scientific notation | 7.45 × |
745 in other forms
| Form | Value |
|---|---|
| In words | seven hundred and forty-five |
| Roman numerals | DCCXLV |
| Binary (base 2) | 1011101001 |
| Octal (base 8) | 1351 |
| Hexadecimal (base 16) | 2E9 |
| Base 3 | 1000121 |
| As time | 745 seconds = 12 min 25 s |
Is 745 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 1) | 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 | Yes (745 ÷ 5 = 149) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 1) | 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 7) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 5) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 8) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 1) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 745 a prime number?
No. 745 = 5 × 149, so it is divisible by 5.
What are the factors of 745?
1, 5, 149, 745.
What is 745 in binary?
1011101001 (hexadecimal 2E9, octal 1351).
What is the square root of 745?
About 27.2947.
What is 745 in Roman numerals?
DCCXLV.
Is 745 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 745?
745 is a semiprime: 5 × 149, the product of two primes.