8741
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 8742
- Proper Divisor Sum (Aliquot Sum)
- 1
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 8740
- Möbius Function
- -1
- Radical
- 8741
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 109
- 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
- yes
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 1090
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Primes of the form k^2 - k - 1.at n=45A002327
- Numbers k such that (15^k - 1)/14 is prime.at n=5A006033
- Numbers k such that the continued fraction for sqrt(k) has period 57.at n=14A020396
- a(n) = T(2n,n+4), T given by A026736.at n=5A026853
- Number of partitions of n into a prime number of parts.at n=38A038499
- Denominators of continued fraction convergents to sqrt(552).at n=4A042057
- Primes for which only two iterations of 'Prime plus its digit sum equals a prime' are possible.at n=39A048524
- Numbers k such that 129*2^k-1 is prime.at n=32A050590
- Discriminants of real quadratic fields with class number 1 and related continued fraction period length of 13.at n=25A050962
- Primes with distinct digits in descending order.at n=43A052014
- Smallest prime in n-th shell of prime spiral.at n=17A053998
- Primes p such that p+7 == 0 (mod phi(p+7)).at n=23A067606
- Integer part of n#/((p-11)# 11#), where p=preceding prime to n.at n=58A102789
- Numbers k such that 10^k + 7*R_k - 4 is prime, where R_k = 11...1 is the repunit (A002275) of length k.at n=8A102942
- Numbers whose anti-divisors sum to a perfect cube.at n=18A109351
- Primes such that the sum of the predecessor and successor primes is divisible by 31.at n=24A113155
- G.f. A(x) equals the limit of the composition of functions (x+x^n) in reverse order; let F_1(x) = x, F_{n+1}(x) = F_n(x) + F_n(x)^(n+1), then A(x) = limit F_n(x): A(x) = ...o x+x^n o ... o x+x^3 o x+x^2 o x.at n=11A119471
- Primes p for which 8*p+1 divides 2^p-1.at n=33A122095
- a(n)*a(n-7) = a(n-1)a(n-6)+a(n-3)+a(n-4) with initial terms a(1)=...=a(7)=1.at n=20A133846
- Mother primes of order 9.at n=26A136068