7984
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 28
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 10
- Divisor Sum
- 15500
- Proper Divisor Sum (Aliquot Sum)
- 7516
- 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
- 3984
- Möbius Function
- 0
- Radical
- 998
- Omega Function (Ω)
- 5
- Little Omega Function (ω)
- 2
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
- 52
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- 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
- yes
- Odd
- no
Appears in sequences
- Numbers whose base-4 representation contains exactly three 0's and three 3's.at n=28A045079
- a(n) = A080313(n)/2.at n=8A080315
- Numerator of 2*Sum(C(n,w)/(2*w+1),w=0..n/2-1)+C(n,n/2)/(n+1) if n is even, or of 2*Sum(C(n,w)/(2*w+1),w=0..(n-1)/2) if n is odd.at n=15A085568
- Terms in a specific cycle of length 29 of the map x->A098189(x).at n=25A098192
- Triangle read by rows: T(n,k) = number of functions from an n-element set into but not onto a k-element set.at n=24A101030
- a(n) is the smallest positive d such that the n-th prime is the smallest prime p for which p+d is also prime.at n=24A101042
- A101042 sorted. There exists a prime p for which a(n) is the smallest positive d such that p is the smallest prime where p+d is also prime.at n=26A101043
- a(n) = a(n-1) + Sum_{k=0..floor(log_2(n-1))} a(2^k), a(1) = 1.at n=27A133147
- a(n) = 5*n^2 + 20*n + 4.at n=37A134547
- Numbers n such that pi(n^2)=pi((n-k)^2)+n, where k=A000193(n).at n=34A137271
- Triangle of coefficients of polynomials H(n,x)=(U^n+L^n)/2+(U^n-L^n)/(2d), where U=x+d, L=x-d, d=(x+4)^(1/2).at n=51A163762
- The magic constants of 6 X 6 magic squares composed of consecutive primes.at n=38A177434
- Number of subsets of {1, 2, ..., n} containing n and having <=8 pairwise coprime elements.at n=37A186992
- Expansion of g.f. -(3*x^2-5*x+1)/(x^3-3*x^2+5*x-1).at n=9A200676
- Numbers of the form (5^j + 7^k)/2, for j and k >= 0.at n=33A226792
- Irregular triangle read by rows: T(n,k) is the number of binary pattern classes in the (9,n)-rectangular grid with k '1's and (9n-k) '0's: two patterns are in same class if one of them can be obtained by a reflection or 180-degree rotation of the other.at n=18A228168
- Irregular triangle read by rows: T(n,k) is the number of binary pattern classes in the (9,n)-rectangular grid with k '1's and (9n-k) '0's: two patterns are in same class if one of them can be obtained by a reflection or 180-degree rotation of the other.at n=22A228168
- The number of binary pattern classes in the (2,n)-rectangular grid with 7 '1's and (2n-7) '0's: two patterns are in same class if one of them can be obtained by a reflection or 180-degree rotation of the other.at n=9A228582
- Number of partitions of n such that (number of distinct parts) > least part.at n=32A239951
- Numbers n such that n + DigitProd(n) = 10^(A055642(n)).at n=4A242945