12156
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 28392
- Proper Divisor Sum (Aliquot Sum)
- 16236
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4048
- Möbius Function
- 0
- Radical
- 6078
- 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
- no
- Narcissistic Number
- no
- Collatz Steps
- 156
- 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
- Convolution of A000203 with itself.at n=28A000385
- "AFK" (ordered, size, unlabeled) transform of 1,2,3,4,...at n=14A032007
- Incrementally largest terms in the continued fraction for Euler's constant gamma (A002852).at n=11A033091
- Number of partitions of n with equal number of parts congruent to each of 1 and 2 (mod 4).at n=48A035543
- Number of partitions of n with equal nonzero number of parts congruent to each of 2 and 4 (mod 5).at n=46A035570
- Structured hexagonal anti-prism numbers.at n=17A100183
- Number of binary words of length n containing at least one subword 10^{9}1 and no subwords 10^{i}1 with i<9.at n=53A143289
- Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0), ending on the vertical axis and consisting of n steps taken from {(-1, -1), (-1, 0), (0, 1), (1, 0), (1, 1)}.at n=8A151432
- Number of nX2 1..4 arrays containing at least one of each value, all equal values connected, rows considered as a single number in nondecreasing order, and columns considered as a single number in decreasing order.at n=8A166838
- a(n) = (7*n^4 + 5*n^2)/12.at n=11A185505
- Number of length n+5 0..3 arrays with no six consecutive terms having five times any element equal to the sum of the remaining five.at n=1A249525
- T(n,k)=Number of length n+5 0..k arrays with no six consecutive terms having five times any element equal to the sum of the remaining five.at n=7A249530
- Number of length 2+5 0..n arrays with no six consecutive terms having five times any element equal to the sum of the remaining five.at n=2A249532
- Number of (n+2)X(2+2) 0..1 arrays with every 3X3 subblock sum of the two medians of the diagonal and antidiagonal minus the sum of the medians of the central row and column nondecreasing horizontally, vertically and ne-to-sw antidiagonally.at n=1A258505
- T(n,k)=Number of (n+2)X(k+2) 0..1 arrays with every 3X3 subblock sum of the two medians of the diagonal and antidiagonal minus the sum of the medians of the central row and column nondecreasing horizontally, vertically and ne-to-sw antidiagonally.at n=4A258511
- Number of (2+2)X(n+2) 0..1 arrays with every 3X3 subblock sum of the two medians of the diagonal and antidiagonal minus the sum of the medians of the central row and column nondecreasing horizontally, vertically and ne-to-sw antidiagonally.at n=1A258512
- Numbers n such that n^2 + 1 has two distinct prime divisors less than n.at n=20A263876
- Length of n-th iterate of the mapping 00->0010, 01->001, 10->000, starting with 00.at n=15A288996
- Number of unlabeled connected simple graphs with n nodes of degree 4 or less, except trees and 4-regular graphs.at n=8A289159
- Consider n equally spaced points along a line and join every pair of points by a semicircle above the line; a(n) is the number of intersection points.at n=25A290447