16925
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 23
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 21018
- Proper Divisor Sum (Aliquot Sum)
- 4093
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 13520
- Möbius Function
- 0
- Radical
- 3385
- Omega Function (Ω)
- 3
- 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
- 40
- 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
- no
- Odd
- yes
Appears in sequences
- Number of partitions of n into parts not of the form 13k, 13k+5 or 13k-5. Also number of partitions with at most 4 parts of size 1 and differences between parts at distance 5 are greater than 1.at n=40A035953
- a(n) = n^3 - n^2 + n - 1 = (n-1) * (n^2 + 1).at n=26A062158
- Number of subsets of the first n numbers having a common divisor greater than 1.at n=28A109511
- Number of trees that have a maximum 'n'.at n=26A168542
- Number of rooted maps with n vertices and 2 faces on a non-orientable surface of type 3/2.at n=2A214335
- Triangle read by rows: T(n,k) = number of rooted maps with n vertices and k faces on a non-orientable surface of type 3/2 (0 <= k <= n).at n=5A214337
- Number of rooted maps with n vertices and n faces on a non-orientable surface of type 3/2.at n=2A214338
- Indices of even terms in A249064.at n=43A249557
- Numbers k such that (5*10^k + 211)/9 is prime.at n=17A295970
- Number of 3Xn 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 2 neighboring 1s.at n=11A297433
- G.f.: Sum_{k>=1} x^(2*k-1)/(1+x^(2*k-1)) * Product_{k>=1} 1/(1-x^k).at n=33A305123
- Numbers k such that k and k + 1 are both Niven numbers in base 3/2 (A342426).at n=33A342427
- Fixed points in A376198.at n=50A376201
- a(n) = Sum_{k=0..n} binomial(n,k) * binomial(3*n+3*k,k).at n=4A388726