16691
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
- 3
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 16692
- Proper Divisor Sum (Aliquot Sum)
- 1
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 16690
- Möbius Function
- -1
- Radical
- 16691
- Omega Function (Ω)
- 1
- Little Omega Function (ω)
- 1
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
- yes
- Composite Number
- no
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- yes
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 1930
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Primes p such that the multiplicative order of 2 modulo p is (p-1)/5.at n=42A001135
- Initial term in sequence of four consecutive primes separated by 3 consecutive differences each <=6 (i.e., when d=2,4 or 6) and forming d-pattern=[2,6,4]; short d-string notation of pattern = [264].at n=21A078848
- Lower triangular matrix T, read by rows, such that row (n) is formed from the sums of adjacent terms in row (n-1) of the matrix square T^2, with T(0,0)=1.at n=22A097710
- Column 1 of triangle A097710, in which row (n) is formed from the sums of the adjacent terms in row (n-1) of the matrix square of A097710.at n=5A097711
- Triangle read by rows: T(n,k) is the number of Schroeder paths of length 2n and having k platforms (i.e., UHD, UHHD, UHHHD, ..., where U=(1,1), D=(1,-1), H=(2,0)).at n=21A104546
- Least prime p of a quartet of 4 distinct primes {p, p+2, q, q+2} such that each digit of q is the same as the corresponding digit of p except that each 6 in p corresponds to a 9 in q and vice versa.at n=3A122712
- Primes congruent to 49 mod 53.at n=35A142579
- Primes congruent to 53 mod 59.at n=32A142780
- Primes congruent to 38 mod 61.at n=34A142836
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (-1, 0, 0), (1, -1, -1), (1, 1, -1), (1, 1, 1)}.at n=8A149601
- a(n) = A000930(n) + A000930(n+3) + 4.at n=23A170933
- Sequence defined by the recurrence formula a(n+1)=sum(a(p)*a(n-p)+k,p=0..n)+l for n>=1, with here a(0)=1, a(1)=8, k=1 and l=-1.at n=6A177178
- Prime numbers > 10000 such that all the substrings of length >= 4 are primes (substrings with leading '0' are considered to be nonprime).at n=21A211686
- Primes p such that p+2 and q are primes, where q is concatenation of binary representations of p and p+2: q = p * 2^L + p+2, where L is the length of binary representation of p+2: L=A070939(p+2).at n=18A232238
- Primes p such that p+2, p+8, and p+12 are all prime.at n=26A233540
- Primes p such that f(f(p)) is prime, where f(x) = x^4 + x^3 + x^2 + x + 1 = A053699(x).at n=16A237445
- Primes p such that p+8, p+888 and p+8888 are also prime.at n=39A241488
- Number of partitions p of n such that (number of numbers in p of form 3k) < (number of numbers in p of form 3k+1).at n=39A241743
- Primes p such that p1 = ceiling(p/2) + p is prime and p2 = floor(p1/2) + p is prime.at n=35A242366
- a(1) = 2; a(n + 1) = smallest prime > a(n) such that a(n + 1) - a(n) is the product of 8 primes.at n=14A285693