Number analysis
365
365 is a composite odd number that factors as 5 × 73.
365 is a composite odd number that factors as 5 × 73.
The number itself
- Value
- 365
- Digits
- 3
- Digit sum
- 14
- Reversed
- 563
- Palindrome
- No
3 + 6 + 5
Digit sum repeated until one digit remains; equals n mod 9 (with 9 for multiples of 9).
Reverses to 563.
Parity and primality
- Parity
- Odd
- Prime
- No
- Prime factorisation
- 5 × 73
- Squarefree
- Yes
- Semiprime
- Yes
- Möbius μ(n)
- 1
- Nearest primes
- 359 ← → 367
Leaves remainder 1 on division by 2.
Composite — it factors as 5 × 73.
2 distinct prime factors, 2 with multiplicity.
No prime divides it twice.
A product of exactly two primes, counted with multiplicity.
(−1) to the power of 2 distinct prime factors.
A gap of 8 between them.
Divisors
- Aliquot sum
- 79
- Classification
- Deficient
1, 5, 73, 365
The proper divisors — everything except n itself.
Its proper divisors fall short by 286.
How many integers from 1 to n share no factor with n.
Sums and additive structure
- Sum of two squares
- Yes
- Sum of three squares
- Yes
- Sum of four squares
- Yes
2² + 19² = 365 · 13² + 14² = 365
Legendre's three-square theorem allows it.
Lagrange's four-square theorem: every non-negative integer is, without exception.
Shapes and sequences
- Figurate shapes
- None
Not triangular, square, pentagonal, hexagonal, cubic, Fibonacci, Lucas, Catalan, factorial or a power of two.
Digit curiosities
- Happy number
- Yes
- Harshad number
- No
- Collatz trajectory
- 94 steps to 1
Repeatedly summing the squares of its digits reaches 1.
Not divisible by its digit sum 14.
Peaks at 9,232 along the way.
Written other ways
- Binary
- 101101101
- Octal
- 555
- Hexadecimal
- 16D
- Base 36
- A5
- Roman numerals
- CCCLXV
- In words
- three hundred and sixty-five
- Scientific notation
- 3.65 × 10^2
Is 365 a prime number?
Composite — it factors as 5 × 73.
Nearby numbers
Other numeral systems
Beyond the bases and Roman numerals above, these notations write 365 their own way.
- Morse code
- · · · − − − · · · · · · · · ·
- Devanagari
- ३६५
- Tamil
- ௩௱௬௰௫
- Thai
- ๓๖๕
References
Further reading: Wikipedia · Wikidata
Notations, naming and the links above come from Wikidata, whose structured data is dedicated to the public domain under CC0-1.0. Retrieved 2026-10-07.