54
domain: N
Properties
Digital Properties
- Digit Count
- 2
- Digit Sum
- 9
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 120
- Proper Divisor Sum (Aliquot Sum)
- 66
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 18
- Möbius Function
- 0
- Radical
- 6
- Omega Function (Ω)
- 4
- 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
- 112
- 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
- vierundfünfzig· ordinal: vierundfünfzigste
- English
- fifty-four· ordinal: fifty-fourth
- Spanish
- cincuenta y cuatro· ordinal: 54º
- French
- cinquante-quatre· ordinal: cinquante-quatrième
- Italian
- cinquantaquattro· ordinal: 54º
- Latin
- quinquaginta quattuor· ordinal: 54.
- Portuguese
- cinquenta e quatro· ordinal: 54º
Appears in sequences
- Expansion of Product_{m >= 1} (1 + x^m); number of partitions of n into distinct parts; number of partitions of n into odd parts.at n=19A000009
- Number of positive integers <= 2^n of form x^2 + 12 y^2.at n=8A000021
- The positive integers. Also called the natural numbers, the whole numbers or the counting numbers, but these terms are ambiguous.at n=53A000027
- Let k = p_1^e_1 p_2^e_2 p_3^e_3 ... be the prime factorization of n. Sequence gives k such that the sum of the numbers of 1's in the binary expansions of e_1, e_2, e_3, ... is odd.at n=25A000028
- Numbers that are not squares (or, the nonsquares).at n=46A000037
- Number of positive integers <= 2^n of form x^2 + y^2.at n=7A000050
- 1-digit numbers arranged in alphabetical order, then the 2-digit numbers arranged in alphabetical order, then the 3-digit numbers, etc.at n=26A000052
- Generalized tangent numbers d(n,1).at n=26A000061
- A Beatty sequence: a(n) = floor(n/(e-2)).at n=38A000062
- Numbers k such that k^4 + 1 is prime.at n=11A000068
- a(n) = Fibonacci(n) - 1.at n=9A000071
- Let A(n) = #{(i,j,k): i^2 + j^2 + k^2 <= n}, V(n) = (4/3)Pi*n^(3/2), P(n) = A(n) - V(n); sequence gives values of n where |P(n)| sets a new record.at n=8A000092
- a(n) = n*(n+3)/2.at n=9A000096
- Number of transformation groups of order n.at n=33A000113
- Number of transformation groups of order n.at n=52A000113
- Denumerants: Expansion of 1/((1-x)*(1-x^2)*(1-x^5)).at n=29A000115
- a(n) = floor(e^n).at n=4A000149
- a(n) = 2*3^n*(2*n)!/(n!*(n+2)!).at n=3A000168
- a(n) = sigma(n), the sum of the divisors of n. Also called sigma_1(n).at n=33A000203
- a(n) = sigma(n), the sum of the divisors of n. Also called sigma_1(n).at n=52A000203