16665
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 24
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 29376
- Proper Divisor Sum (Aliquot Sum)
- 12711
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 8000
- Möbius Function
- 1
- Radical
- 16665
- Omega Function (Ω)
- 4
- Little Omega Function (ω)
- 4
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
- 159
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- 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
- Denominators of cosecant numbers: -2*(2^(2*n-1)-1)*Bernoulli(2*n).at n=50A001897
- a(n) = a(n-1) + a(n-5); a(0) = ... = a(4) = 1.at n=37A003520
- Expansion of 1/(1 -x^5 -x^6 -x^7 - ...).at n=42A017899
- Positive numbers k such that k and 3*k are anagrams in base 7 (written in base 7).at n=27A023069
- When squared gives number composed of digits {2, 5, 7}.at n=7A030487
- Numbers whose base-4 representation contains exactly three 0's and four 1's.at n=30A045032
- Numbers with exactly 4 distinct palindromic prime factors.at n=40A046402
- Odd numbers with exactly 4 distinct palindromic prime factors.at n=4A046406
- Beastly (or hateful) numbers: numbers containing the string 666 in their decimal expansion.at n=30A051003
- Pair the odd numbers such that the k-th pair is (r, r+2k) where r is the smallest odd number not included earlier: (1, 3), (5, 9), (7, 13), (11, 19), (15, 25), (17, 29), (21, 35), (23, 39), (27, 45), ... This is the sequence of the product of the members of pairs.at n=31A075320
- Triangle read by rows: T(n,k) = (n+1,k)-th element of (M^10-M)/9, where M is the infinite lower Pascal's triangle matrix, 1<=k<=n.at n=17A096044
- Sum C(n-4k,k-1), k=0..floor(n/5).at n=41A099562
- a(n) = (n in base 10) * (n in base 2).at n=15A127906
- Tenth column of triangle A035342.at n=2A132055
- Numbers k such that k and k^2 use only the digits 1, 2, 5, 6 and 7.at n=38A137004
- Number of nX2 1..3 arrays containing at least one of each value, all equal values connected, and rows considered as a single number in nondecreasing order.at n=15A166776
- Integers n such that 6n, 36n, and 216n fall between pairs of twin primes, that is, 6n-1, 6n+1, 36n-1, 36n+1, 216n-1, and 216n+1 are prime.at n=13A192851
- Antidiagonal sums of the convolution array A213505.at n=8A213547
- Murai Chuzen numbers.at n=32A225488
- Number of partitions of n having (sum of odd parts) = (sum of even parts).at n=52A239261