64
domain: N
Properties
Digital Properties
- Digit Count
- 2
- Digit Sum
- 10
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 7
- Divisor Sum
- 127
- Proper Divisor Sum (Aliquot Sum)
- 63
- 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
- 32
- Möbius Function
- 0
- Radical
- 2
- Omega Function (Ω)
- 6
- Little Omega Function (ω)
- 1
Special
- Factorial
- no
- Catalan Number
- no
- Bell Number
- no
- Motzkin Number
- no
- Primorial
- no
Figurate Numbers
- Fibonacci Number
- no
- Triangular Number
- no
- Perfect Square
- yes
- Perfect Cube
- yes
- 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
- 6
- Smith Number
- no
Classification
- Natural
- yes
- Even
- yes
- Odd
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- yes
- Achilles Number
- no
- Perfect Power
- yes
- Smooth Number
- yes
- Carmichael Number
- no
Names
- German
- vierundsechzig· ordinal: vierundsechzigste
- English
- sixty-four· ordinal: sixty-fourth
- Spanish
- sesenta y cuatro· ordinal: 64º
- French
- soixante-quatre· ordinal: soixante-quatrième
- Italian
- sessantaquattro· ordinal: 64º
- Latin
- sexaginta quattuor· ordinal: 64.
- Portuguese
- sessenta e quatro· ordinal: 64º
Appears in sequences
- Number of ways of making change for n cents using coins of 1, 2, 5, 10 cents.at n=25A000008
- 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=20A000009
- Smallest prime power >= n.at n=61A000015
- Smallest prime power >= n.at n=62A000015
- Smallest prime power >= n.at n=63A000015
- The positive integers. Also called the natural numbers, the whole numbers or the counting numbers, but these terms are ambiguous.at n=63A000027
- Generalized tangent numbers d(n,1).at n=27A000061
- Generalized tangent numbers d(n,1).at n=31A000061
- A Beatty sequence: a(n) = floor(n/(e-2)).at n=45A000062
- Odious numbers: numbers with an odd number of 1's in their binary expansion.at n=32A000069
- a(n) = floor(n^(3/2)).at n=16A000093
- Number of ways of writing n as a sum of 4 squares; also theta series of four-dimensional cubic lattice Z^4.at n=7A000118
- Cake numbers: maximal number of pieces resulting from n planar cuts through a cube (or cake): C(n+1,3) + n + 1.at n=7A000125
- Number of labeled rooted trees with n nodes: n^(n-1).at n=3A000169
- Lower Wythoff sequence (a Beatty sequence): a(n) = floor(n*phi), where phi = (1+sqrt(5))/2 = A001622.at n=39A000201
- a(8i+j) = 13i + a(j), where 1<=j<=8.at n=39A000202
- Generalized class numbers c_(n,1).at n=6A000233
- Powers of 4: a(n) = 4^n.at n=3A000302
- Number of binary necklaces of length n with no subsequence 00, excluding the necklace "0".at n=13A000358
- Sums of three squares: numbers of the form x^2 + y^2 + z^2.at n=54A000378