Number analysis
82
82 is a composite even number that factors as 2 × 41.
82 is a composite even number that factors as 2 × 41.
The number itself
- Value
- 82
- Digits
- 2
- Digit sum
- 10
- Reversed
- 28
- Palindrome
- No
8 + 2
Digit sum repeated until one digit remains; equals n mod 9 (with 9 for multiples of 9).
Reverses to 28.
Parity and primality
- Parity
- Even
- Prime
- No
- Prime factorisation
- 2 × 41
- Squarefree
- Yes
- Semiprime
- Yes
- Möbius μ(n)
- 1
- Nearest primes
- 79 ← → 83
Divisible by 2.
Composite — it factors as 2 × 41.
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 4 between them.
Divisors
- Aliquot sum
- 44
- Classification
- Deficient
1, 2, 41, 82
The proper divisors — everything except n itself.
Its proper divisors fall short by 38.
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
- Goldbach pair
- 3 + 79
1² + 9² = 82
Legendre's three-square theorem allows it.
Lagrange's four-square theorem: every non-negative integer is, without exception.
The smallest pair of primes summing to n. Goldbach’s conjecture says one always exists; it remains unproven.
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
- 110 steps to 1
Repeatedly summing the squares of its digits reaches 1.
Not divisible by its digit sum 10.
Peaks at 9,232 along the way.
Written other ways
- Binary
- 1010010
- Octal
- 122
- Hexadecimal
- 52
- Base 36
- 2A
- Roman numerals
- LXXXII
- In words
- eighty-two
- Scientific notation
- 8.2 × 10^1
Is 82 a prime number?
Composite — it factors as 2 × 41.
Nearby numbers
Other numeral systems
Beyond the bases and Roman numerals above, these notations write 82 their own way.
- Greek (alphabetic)
- ΠΒʹ
- Babylonian cuneiform
- 𒐕𒎙𒐖
- Tamil
- ௮௰௨
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.