57
domain: N
Properties
Digital Properties
- Digit Count
- 2
- Digit Sum
- 12
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 80
- Proper Divisor Sum (Aliquot Sum)
- 23
- 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
- 36
- Möbius Function
- 1
- Radical
- 57
- Omega Function (Ω)
- 2
- 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
- no
- Narcissistic Number
- no
- Collatz Steps
- 32
- Smith Number
- no
Classification
- Natural
- yes
- Even
- no
- Odd
- yes
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- Squarefree Number
- yes
- 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
- no
- Carmichael Number
- no
Names
- German
- siebenundfünfzig· ordinal: siebenundfünfzigste
- English
- fifty-seven· ordinal: fifty-seventh
- Spanish
- cincuenta y siete· ordinal: 57º
- French
- cinquante-sept· ordinal: cinquante-septième
- Italian
- cinquantasette· ordinal: 57º
- Latin
- quinquaginta septem· ordinal: 57.
- Portuguese
- cinquenta e sete· ordinal: 57º
Appears in sequences
- Mosaic numbers or multiplicative projection of n: if n = Product (p_j^k_j) then a(n) = Product (p_j * k_j).at n=56A000026
- The positive integers. Also called the natural numbers, the whole numbers or the counting numbers, but these terms are ambiguous.at n=56A000027
- Numbers that are not squares (or, the nonsquares).at n=49A000037
- 1-digit numbers arranged in alphabetical order, then the 2-digit numbers arranged in alphabetical order, then the 3-digit numbers, etc.at n=29A000052
- A Beatty sequence: a(n) = floor(n/(e-2)).at n=40A000062
- Number of partitions of n if there are two kinds of 1, two kinds of 2 and two kinds of 3.at n=6A000098
- Maximal number of regions obtained by joining n points around a circle by straight lines. Also number of regions in 4-space formed by n-1 hyperplanes.at n=6A000127
- a(n) = sigma(n), the sum of the divisors of n. Also called sigma_1(n).at n=48A000203
- Tribonacci numbers: a(n) = a(n-1) + a(n-2) + a(n-3) with a(0)=a(1)=a(2)=1.at n=8A000213
- Remove all factors of 2 from n; or largest odd divisor of n; or odd part of n.at n=56A000265
- 3*n - 2*floor(sqrt(4*n+5)) + 5.at n=24A000277
- Expansion of cos(x)/cos(2x).at n=2A000281
- Eulerian numbers (Euler's triangle: column k=2 of A008292, column k=1 of A173018).at n=6A000295
- Generalized class numbers c_(n,2).at n=1A000362
- Sums of three squares: numbers of the form x^2 + y^2 + z^2.at n=49A000378
- 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=29A000379
- Numbers of form x^2 + y^2 + 7z^2.at n=46A000394
- Numbers of form x^2 + 2y^2 + 2yz + 4z^2.at n=52A000398
- Numbers of form x^2 + y^2 + 2*z^2.at n=53A000401
- Coefficients of iterated exponentials.at n=2A000406