16191
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 26832
- Proper Divisor Sum (Aliquot Sum)
- 10641
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 9216
- Möbius Function
- 0
- Radical
- 5397
- 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
- 115
- 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
- Strobogrammatic numbers: the same upside down.at n=46A000787
- Reversion of (1 + g.f. for primes).at n=8A007296
- Number of partitions of n into parts not of the form 21k, 21k+10 or 21k-10. Also number of partitions with at most 9 parts of size 1 and differences between parts at distance 9 are greater than 1.at n=37A035988
- A sequence derived from a truncated Pascal's Triangle matrix.at n=5A095262
- Number of A095748-primes in range ]2^n,2^(n+1)].at n=27A095758
- Base 10 numbers that are palindromic in bases 2 and 4.at n=43A097856
- Numbers that are the same upside down (using only digits 0, 1, 6 and 9).at n=28A169731
- Number of (n+1)X(n+1) -10..10 symmetric matrices with every 2X2 subblock having sum zero and one, two or three distinct values.at n=5A211817
- Numbers which do not reach zero under either of the iterations: x -> floor(sqrt(x)) * (x - floor(sqrt(x))^2) or y -> ceiling(sqrt(y)) * (ceiling(sqrt(y))^2 - y).at n=15A219963
- Binary palindromic numbers with only two 0 bits, both in the middle.at n=5A220236
- Numbers whose binary representation is palindromic and in which all runs of 0's and 1's have length at least 2.at n=51A222813
- Strobogrammatic nonpalindromic numbers.at n=23A287092
- On a spirally numbered square grid, with labels starting at 1, this is the number of the last cell that an (n,n+1) leaper reaches before getting trapped, or -1 if it never gets trapped.at n=19A343179
- E.g.f. F(x) satisfies F_{n}(0) = (-F_{n-1}(0) + Sum_{k=0..n-1} (F_{k}(0)*(-1)^(n-k+1)*binomial(n+1,k)))/n, with F_{0}(0) = -1, where F_{k}(x) is the k-th derivative of F(x).at n=8A373174
- Expansion of 1/(1 - 9*x*(1 + x))^(4/3).at n=4A377260
- Numbers of the form A073138(k) XOR A038573(k).at n=48A380544
- Odd numbers m such that at least one of the factors of Stern polynomial B(m,x) has at least one negative coefficient.at n=13A389915