7898
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 32
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 12960
- Proper Divisor Sum (Aliquot Sum)
- 5062
- 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
- 3580
- Möbius Function
- -1
- Radical
- 7898
- Omega Function (Ω)
- 3
- Little Omega Function (ω)
- 3
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
- 39
- 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
- yes
- Odd
- no
Appears in sequences
- Number of stacks, or planar partitions of n; also weakly unimodal compositions of n.at n=19A001523
- Hoggatt sequence with parameter d=4.at n=6A005362
- Sum of digits = 8 times number of digits.at n=20A061425
- a(n) = floor(n^log(n)).at n=19A061567
- Start with 0; to get next term reverse digits and add 1 to each digit (9's get replaced by 10's).at n=27A061729
- Positions of powers of 2 in A064413.at n=13A064954
- Numbers k such that sigma(k) = phi(k+1) + phi(k-1).at n=5A068401
- Bisection of A001523.at n=9A100506
- Triangle read by rows: row n (n >= 0) consists of the elements g(i, n-i) (0 <= i <= n), where g(r,s) = 1 + Sum_{k=1..r} Product_{i=0..k-1} binomial(r+s-1, s+i) / binomial(r+s-1, i).at n=61A116925
- a(1) = 3, a(2) = 4. a(n) = (largest composite which occurs earlier in sequence) + (largest prime which occurs earlier in sequence).at n=24A120365
- Records in A018892.at n=45A126097
- a(0)=1; for n > 0, a(n) = a(n-1) + a(prime(n)(mod n)), where prime(n) is the n-th prime.at n=43A127066
- Right-angled numbers with an internal digit as the vertex.at n=43A135602
- Numbers n such that n!8-1 is prime.at n=49A204662
- Number of nondecreasing -3..3 vectors of length n whose dot product with some nondecreasing -3..3 vector equals n.at n=9A226406
- Numbers n such that A257378(n)=A257379(n), so the prime numbers k*n*2^n-1 and k*n*2^n+1 are twin primes for the smallest k such that k*n*2^n-1 is a prime number.at n=18A256823
- Number of n-digit semiprimes whose prime factors concatenated larger to the right of smaller form an n-digit prime (in decimal).at n=5A259493
- Number of sets of exactly six positive integers <= n having a square element sum.at n=18A281866
- Numbers whose smallest decimal digit is 7.at n=41A284068
- Number of integer partitions of n in which the even parts appear as often at even positions as at odd positions.at n=37A300787