13951
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 15952
- Proper Divisor Sum (Aliquot Sum)
- 2001
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 11952
- Möbius Function
- 1
- Radical
- 13951
- 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
- 89
- 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
- Base 9 digits are, in order, the first n terms of the periodic sequence with initial period 2,1,1.at n=4A037558
- a(n) = n-th centered n-gonal number.at n=30A100119
- Numbers whose Matula tree is a binary tree (i.e., root has degree 2 and all nodes except root and leaves have degree 3).at n=14A111299
- Semiprimes (A001358) whose digit reversal is a triangular number.at n=39A115741
- Least positive k such that 10^n + {k, k+2, k+6, k+8} are all prime.at n=7A121066
- Number of distinct angles in all integer-sided triangles with all sides <= n.at n=43A123325
- a(n) = 62*n^2 + 1.at n=15A158676
- Number of lines through at least 2 points of a 6 X n grid of points.at n=41A160846
- Partial sums of round(5^n/7).at n=7A178873
- Number of ordered triples (i,j,k) with |i|, |j|, |k|, |i*j*k| <= n.at n=31A226359
- a(n) = 7*n^2 - 5*n + 1.at n=45A239449
- Triangle read by rows: row n>=1 contains in increasing order the Matula numbers of the rooted binary trees with n leaves.at n=15A245824
- a(n) = A273059(4n+3).at n=20A275919
- Decimal representation of the x-axis, from the origin to the right edge, of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 315", based on the 5-celled von Neumann neighborhood.at n=13A281046
- Solution of the complementary equation a(n) = 2*a(n-1) - a(n-2) + b(n-1) -2, where a(0) = 1, a(1) = 2, b(0) = 3, and (a(n)) and (b(n)) are increasing complementary sequences.at n=41A294868
- Matula-Goebel numbers of rooted trees in which all positive outdegrees are the same.at n=42A298424
- Matula-Goebel numbers of unlabeled binary rooted semi-identity trees.at n=9A339193
- a(n) = Sum_{i=1..n} (prime(i+1)-prime(i))*prime(n+1-i).at n=42A343531
- Matula-Goebel number of the rooted binary tree with Colijn-Plazzotta number n.at n=17A356121
- Number of subsets of {1..n} whose cardinality is not the sum of two distinct elements.at n=15A367400