Number analysis
190
190 is a composite even number that factors as 2 × 5 × 19.
190 is a composite even number that factors as 2 × 5 × 19.
The number itself
- Value
- 190
- Digits
- 3
- Digit sum
- 10
- Reversed
- 91
- Palindrome
- No
1 + 9 + 0
Digit sum repeated until one digit remains; equals n mod 9 (with 9 for multiples of 9).
Reverses to 91.
Parity and primality
- Parity
- Even
- Prime
- No
- Prime factorisation
- 2 × 5 × 19
- Squarefree
- Yes
- Möbius μ(n)
- -1
- Nearest primes
- 181 ← → 191
Divisible by 2.
Composite — it factors as 2 × 5 × 19.
3 distinct prime factors, 3 with multiplicity.
No prime divides it twice.
(−1) to the power of 3 distinct prime factors.
A gap of 10 between them.
Divisors
- Aliquot sum
- 170
- Classification
- Deficient
1, 2, 5, 10, 19, 38, 95, 190
The proper divisors — everything except n itself.
Its proper divisors fall short by 20.
How many integers from 1 to n share no factor with n.
Sums and additive structure
- Sum of two squares
- No
- Sum of three squares
- Yes
- Sum of four squares
- Yes
- Goldbach pair
- 11 + 179
A prime congruent to 3 mod 4 divides it an odd number of times, which rules it out.
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
- Triangular number
- Yes — the 19th
- Hexagonal number
- Yes — the 10th
Digit curiosities
- Happy number
- Yes
- Harshad number
- Yes
- Collatz trajectory
- 106 steps to 1
Repeatedly summing the squares of its digits reaches 1.
Divisible by its digit sum 10 — 190 ÷ 10 = 19.
Peaks at 9,232 along the way.
Written other ways
- Binary
- 10111110
- Octal
- 276
- Hexadecimal
- BE
- Base 36
- 5A
- Roman numerals
- CXC
- In words
- one hundred and ninety
- Scientific notation
- 1.90 × 10^2
Is 190 a prime number?
Composite — it factors as 2 × 5 × 19.
Nearby numbers
Other numeral systems
Beyond the bases and Roman numerals above, these notations write 190 their own way.
- Morse code
- · − − − − − − − − · − − − − −
- Devanagari
- १९०
- Tamil
- ௱௯௰
- Thai
- ๑๙๐
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.