50
domain: N
Properties
Digital Properties
- Digit Count
- 2
- Digit Sum
- 5
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 93
- Proper Divisor Sum (Aliquot Sum)
- 43
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 20
- Möbius Function
- 0
- Radical
- 10
- Omega Function (Ω)
- 3
- Little Omega Function (ω)
- 2
Special
- Factorial
- no
- Catalan Number
- no
- Bell Number
- no
- Motzkin Number
- no
- Primorial
- no
Figurate Numbers
- Fibonacci Number
- no
- Triangular Number
- no
- Perfect Square
- no
- Perfect Cube
- no
- Pentagonal Number
- no
- Hexagonal Number
- no
- Lucas Number
- no
- Tetrahedral Number
- no
- Pell Number
- no
- Tribonacci Number
- no
- Pronic Number
- no
Recreational
- Happy Number
- no
- Harshad Number
- yes
- Narcissistic Number
- no
- Collatz Steps
- 24
- Smith Number
- no
Classification
- Natural
- yes
- Even
- yes
- Odd
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- Prime Power
- no
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Perfect Power
- no
- Smooth Number
- yes
- Carmichael Number
- no
Names
- German
- fünfzig· ordinal: fünfzigste
- English
- fifty· ordinal: fiftieth
- Spanish
- cincuenta· ordinal: 50º
- French
- cinquante· ordinal: cinquantième
- Italian
- cinquanta· ordinal: 50º
- Latin
- quinquaginta· ordinal: 50.
- Portuguese
- cinquenta· ordinal: 50º
Appears in sequences
- Number of groups of order n.at n=72A000001
- The positive integers. Also called the natural numbers, the whole numbers or the counting numbers, but these terms are ambiguous.at n=49A000027
- Numbers that are not squares (or, the nonsquares).at n=42A000037
- 1-digit numbers arranged in alphabetical order, then the 2-digit numbers arranged in alphabetical order, then the 3-digit numbers, etc.at n=23A000052
- Local stops on New York City 1 Train (Broadway-7 Avenue Local) subway.at n=6A000053
- Local stops on New York City A line subway.at n=5A000054
- Generalized tangent numbers d(n,1).at n=25A000061
- A Beatty sequence: a(n) = floor(n/(e-2)).at n=35A000062
- Partial sums of (unordered) ways of making change for n cents using coins of 1, 2, 5, 10 cents.at n=10A000064
- Odious numbers: numbers with an odd number of 1's in their binary expansion.at n=25A000069
- Number of simplicial polyhedra with n vertices; simple planar graphs with n vertices and 3n-6 edges; maximal simple planar graphs with n vertices; planar triangulations with n vertices; triangulations of the sphere with n vertices; 3-connected cubic planar graphs on 2n-4 vertices.at n=6A000109
- Number of ways of folding a strip of n labeled stamps.at n=4A000136
- Lower Wythoff sequence (a Beatty sequence): a(n) = floor(n*phi), where phi = (1+sqrt(5))/2 = A001622.at n=30A000201
- a(8i+j) = 13i + a(j), where 1<=j<=8.at n=30A000202
- Unsigned Stirling numbers of first kind, s(n+1,2): a(n+1) = (n+1)*a(n) + n!.at n=4A000254
- 3*n - 2*floor(sqrt(4*n+5)) + 5.at n=21A000277
- Sums of three squares: numbers of the form x^2 + y^2 + z^2.at n=43A000378
- Numbers where total number of 1-bits in the exponents of their prime factorization is even; a 2-way classification of integers: complement of A000028.at n=25A000379
- Numbers of form x^2 + y^2 + 7z^2.at n=41A000394
- Numbers of form x^2 + 2y^2 + 2yz + 4z^2.at n=45A000398