8226
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 17862
- Proper Divisor Sum (Aliquot Sum)
- 9636
- 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
- 2736
- Möbius Function
- 0
- Radical
- 2742
- Omega Function (Ω)
- 4
- Little Omega Function (ω)
- 3
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
- 39
- Smith Number
- no
- Vampire Number
- 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
- no
- Carmichael Number
- no
Classification
- Even
- yes
- Odd
- no
Appears in sequences
- a(n+1) = n*a(n) - (-1)^n.at n=7A003048
- a(n) = floor(n*(n-1)*(n-2)*(n-3)/31).at n=24A011941
- Convolution of Bell and Catalan numbers.at n=8A014327
- Numbers whose base-4 representation contains exactly four 0's and no 1's.at n=26A045033
- Numbers whose base-4 representation contains exactly four 0's and three 2's.at n=1A045060
- 15-gonal (or pentadecagonal) numbers: n*(13n-11)/2.at n=36A051867
- Numbers k such that k^2 contains only digits {0,6,7}, not ending with zero.at n=1A058449
- Numbers which are the sum of their proper divisors containing the digit 4.at n=10A059463
- Interprimes which are of the form s*prime, s=18.at n=21A075293
- Numbers k such that (k / sum of digits of k) and (k+1 / sum of digits of k+1) are both prime.at n=10A085775
- a(1) = 1; for n>1, a(n) = n*a(n-1) + 1 if n is a prime else a(n) = n*a(n-1) - 1.at n=6A093463
- Triangle read by rows: T(n,k) = number of peakless Motzkin paths of length n containing k subwords of the type uh^ju, dH^jd, or dh^ju for some j>0, where u=(1,1), d=(1,-1) and h=(1,0) (can be easily expressed using RNA secondary structure terminology).at n=56A098056
- Number of peakless Motzkin paths with no U H^j U, no D H^j D and no D H^jU (j>0), where U=(1,1), D=(1,-1) and H=(1,0) (can be easily expressed using RNA secondary structure terminology).at n=17A098057
- Small-number statistic from the enumeration of domino tilings of a 7-pillow of order n.at n=15A112841
- Numbers k such that k and k^2 use only the digits 0, 2, 6, 7 and 8.at n=5A136922
- Smallest number k such that k^n is the sum of numbers in a twin prime pair.at n=46A195336
- Number of values of k for which sigma(k) is a permutation of decimal digits of k, for k < 2^n.at n=26A216392
- Number of (n+2)X5 0..2 matrices with each 3X3 subblock idempotent.at n=11A224601
- Number of non-equivalent binary n X n matrices with two nonadjacent 1's.at n=18A232567
- Number of partitions p of n such that m(p) < m(c(p)), where m = minimal multiplicity of parts, and c = conjugate.at n=52A240729