8139
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 10856
- Proper Divisor Sum (Aliquot Sum)
- 2717
- 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
- 5424
- Möbius Function
- 1
- Radical
- 8139
- 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
- 114
- Smith Number
- no
- Vampire Number
- no
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
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 89.at n=19A031587
- Expansion of (1-x)/(1-2*x-x^2-2*x^3).at n=10A077996
- a(1) = 1; a(n) = Sum_{k=1..n-1} a(floor((n-1)/k)).at n=42A078346
- Numbers n such that nextprime(n^3)-prevprime(n^3) = 4.at n=38A090121
- Numbers n such that the partition function A000041(k) is even and odd the same number of times for 0 <= k <= n.at n=18A098936
- Triangle read by rows: T(n,k) is the number of k-matchings in the C_n X P_3 graph (C_n is the cycle graph on n vertices and P_3 is the path graph on 3 vertices).at n=28A102089
- Number of Fermat pseudoprimes to bases 2 and 3 less than 10^n.at n=10A114246
- G.f. satisfies A(x) = 1 + x*(1 + x*A(x)^6)^3.at n=6A137969
- A triangular sequence:f(n)=Sum[StirlingS2[n, k], {k, 1, n}];t(n,m)=Binomial[n, m]*f(m + 1)*f(n - m + 1)-Binomial[n,0]*f(1)*f(n+1)+1.at n=29A174639
- A triangular sequence:f(n)=Sum[StirlingS2[n, k], {k, 1, n}];t(n,m)=Binomial[n, m]*f(m + 1)*f(n - m + 1)-Binomial[n,0]*f(1)*f(n+1)+1.at n=34A174639
- Minimal nonnegative integer that cannot be represented as the sum of an m-gonal and a k-gonal number for any k,m less than n.at n=8A176874
- Numbers k such that (k^3 - 2, k^3 + 2) is a pair of cousin primes (see A178227).at n=37A178228
- Number of (n+2) X 6 binary arrays with every 3 X 3 subblock commuting with each horizontal and vertical neighbor 3 X 3 subblock.at n=14A190028
- First time n appears in the first differences of n*log(n): A217865.at n=10A217976
- Number of partitions p of n including round(mean(p)) as a part. (This is "Mathematica round").at n=35A241338
- The 300-degree spoke (or ray) of a hexagonal spiral of Ulam.at n=26A244804
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 1006", based on the 5-celled von Neumann neighborhood.at n=26A273861
- Number of compositions of n if only the order of the even numbers matter.at n=24A275592
- Number of total dominating sets in the complement graph of the n-cycle.at n=10A347477
- Number of integer partitions of n whose multiplicities have integer median.at n=32A360687