15683
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
- 2
- Divisor Sum
- 15684
- 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
- 15682
- Möbius Function
- -1
- Radical
- 15683
- 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
- 53
- 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
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- yes
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 1831
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- a(0)=2; for n>=1, a(n) = smallest prime p such that there is a gap of exactly 2n between p and next prime, or -1 if no such prime exists.at n=22A000230
- Primes (lower end) with record gaps to the next consecutive prime: primes p(k) where p(k+1) - p(k) exceeds p(j+1) - p(j) for all j < k.at n=11A002386
- Increasing gaps between prime-powers.at n=16A002540
- a(n) = floor(3rd elementary symmetric function of Sum_{j=1..k} 1/j, k = 1,2,...,n).at n=15A025213
- a(n) = Min{ q prime | nextprime(q) - q - 1 = prime(n)}, or 0 if none exist.at n=12A063793
- Primes for which the four closest primes are smaller.at n=33A075030
- Primes for which the five closest primes are smaller.at n=6A075037
- Primes for which the six closest primes are smaller.at n=2A075038
- Primes for which the seven closest primes are smaller.at n=0A075043
- Primes for which the eight closest primes are smaller.at n=0A075050
- Smallest prime for which the n closest primes are smaller.at n=6A075051
- Smallest prime for which the n closest primes are smaller.at n=7A075051
- Safe primes (A005385) (p and (p-1)/2 are primes) such that 12*p+1 is also prime.at n=41A075707
- Smallest prime(k) such that 2^n divides the product of composite numbers between prime(k) and prime(k+1) but 2^(n+1) does not.at n=41A077216
- a(1)=2; a(n) for n>1 is the smallest prime number > a(n-1) such that the concatenation of all previous terms is also prime.at n=28A080155
- a(n) is the smallest prime p of the form 4k+3 such that nextprime(p) - p = 4n.at n=10A082098
- Primes p such that (r-p)/log(p) > 4, where r is the next prime after p.at n=1A082889
- Smallest prime dividing the composite number consisting of A089017(n) successive 3's followed by a terminal 1.at n=35A089018
- Erroneous version of A002540.at n=17A094158
- a(n) = prime(prime(A096480(n))).at n=21A096482