7917
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 24
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 13440
- Proper Divisor Sum (Aliquot Sum)
- 5523
- 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
- 4032
- Möbius Function
- 1
- Radical
- 7917
- 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
- 145
- 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
- Denominator of (2n+1)(2n+2) B_{2n}, where B_n are the Bernoulli numbers. Also denominators of the asymptotic expansion of the polygamma function psi'''(z).at n=43A006956
- a(n) = n*(9*n - 1)/2.at n=42A022266
- Fibonacci sequence beginning 0, 21.at n=14A022355
- One fifth of octo-factorial numbers.at n=3A034911
- Number of partitions of n into parts not of the form 17k, 17k+8 or 17k-8. Also number of partitions with at most 7 parts of size 1 and differences between parts at distance 7 are greater than 1.at n=34A035969
- Numbers n such that the cyclotomic polynomial of order n has a nonzero coefficient which does not appear in any cyclotomic polynomials of lower order.at n=11A046887
- a(n)=T(n,n+1), array T as in A049735.at n=35A049741
- Odd values of the PartitionsQ function A000009.at n=12A051044
- Number of partitions of n such that all parts are neither relatively prime (cf. A000837) nor are they periodic with each part occurring the same number of times (cf. A024994).at n=63A060034
- Numbers n such that both n^4 + 2 and n^4 - 2 are prime.at n=33A071351
- Coefficient of q^1 in nu(n), where nu(0)=1, nu(1)=b and, for n>=2, nu(n)=b*nu(n-1)+lambda*(1+q+q^2+...+q^(n-2))*nu(n-2) with (b,lambda)=(1,3).at n=10A074355
- a(n) is the unique odd positive solution x of 2^n = 7x^2+y^2.at n=27A077020
- a(n) = (2*n+5)*(2*n+1).at n=43A078371
- Number of ways to partition 2n+1 into distinct positive integers.at n=28A078408
- Number of ways to partition 4*n+1 into distinct positive integers.at n=14A078409
- a(n) = F(4)*F(n)*F(n+1) + F(5)*F(n+1)^2 if n odd, a(n) = F(4)*F(n)*F(n+1) + F(5)*F(n+1)^2 - F(5) if n even, where F(n) is the n-th Fibonacci number (A000045).at n=8A080144
- a(n) = (4*n+3)*(4*n+7).at n=21A085027
- Triangle of binary products of Fibonacci numbers.at n=48A094568
- Lucas and Lehmer numbers with parameters (1 +- sqrt(-7))/2.at n=28A107920
- 4-almost primes equal to the product of two successive semiprimes.at n=29A108215