13987
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 28
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 14256
- Proper Divisor Sum (Aliquot Sum)
- 269
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 13720
- Möbius Function
- 1
- Radical
- 13987
- 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
- 107
- 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
- Number of ternary rooted trees with n nodes and height at most 6.at n=15A036374
- Number of partitions of n such that cn(0,5) = cn(2,5) <= cn(3,5) = cn(4,5) <= cn(1,5).at n=61A036846
- Numbers k such that Euler phi(k) / Carmichael lambda(k) = 14.at n=31A066696
- Centered 21-gonal numbers.at n=36A069178
- Numbers m not of the form k*(k+2) that have a single '1' in the periodic part of the continued fraction of sqrt(n).at n=41A102538
- a(1) = 1 then the least multiple of odd numbers not odd multiples of 5, (3,7,9,11,13,17,19,21,23,27,29,...) such that every partial concatenation is noncomposite.at n=28A110433
- Number of partitions p of n such that neither floor(mean(p)) nor ceiling(mean(p)) is a part.at n=42A241343
- Strings of 5 digits from 1...9, such that no formula using the single digits in the given order exists that evaluates to 0.at n=15A288355
- Number of connected undirected unlabeled loopless multigraphs with 4 vertices and n edges.at n=30A290778
- Composite numbers k such that the sum of their aliquot parts divides k+1.at n=9A306532
- a(n) = Sum_{d|n} (pod(d)/d), where pod(k) is the product of the divisors of k (A007955).at n=23A322671
- Squarefree MM-numbers of strict uniform regular multiset systems spanning an initial interval of positive integers.at n=30A322703
- Number of geometry-minimal periodic tilings of the hyperbolic plane with Dress-complexity n.at n=11A335697
- Number of odd-length integer partitions of n with integer alternating product.at n=48A347444
- a(n) is the number of free polyominoes of width 2 and size n.at n=16A352720
- Triangle read by rows: T(n,k) = number of collections of up to k subsets of [n] covering [n], with [0]={}; n>=0, k=0..2^n.at n=25A381683