17681
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
- 4
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 17682
- 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
- 17680
- Möbius Function
- -1
- Radical
- 17681
- 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
- 79
- 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
- yes
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 2031
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Expansion of 1/((1-2x)(1-5x)(1-9x)).at n=4A016298
- Primes of the form k^2 - 8.at n=30A028886
- Sums of 5 distinct powers of 4.at n=31A038473
- Irregular primes with irregularity index three.at n=27A060975
- Number of paths of length n+2 originating at a non-corner edge of 4 X 4 Boggle board.at n=14A063001
- Primes which can be expressed as sum of distinct powers of 4.at n=24A077718
- Lesser of twin primes (p,q=p+2) such that p*q-p-q and p*q+p+q are primes.at n=2A126334
- Primes p such that p*q-p-q and p*q+p+q are prime where q=nextprime(p).at n=36A128548
- Lesser of twin primes isolated from neighboring primes by +- 10 (or more).at n=34A138063
- Running prime totals of prime factors (without multiplicity) of consecutive composite N.at n=40A140610
- Primes congruent to 9 mod 47.at n=37A142360
- Primes congruent to 32 mod 53.at n=37A142562
- Primes congruent to 40 mod 59.at n=31A142767
- Primes congruent to 52 mod 61.at n=33A142850
- Square array A(n,k), n>=1, k>=1, read by antidiagonals: A(n,k) = Fibonacci rabbit sequence number n coded in base k.at n=32A144287
- a(n) = A145818(2n-1).at n=45A145850
- Primes p such that the multiplicative order of 2 modulo p is (p-1)/10.at n=27A152310
- Number of ways to select disjoint subsets out of {1..n} such that their (sorted) element sums give the list of divisors of n.at n=56A164988
- The smaller member of a twin prime pair in which both primes are emirps.at n=32A175215
- Sum_{k>0} (n mod k) * 2^(n-k).at n=15A178924