7938
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 27
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 30
- Divisor Sum
- 20691
- Proper Divisor Sum (Aliquot Sum)
- 12753
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 2268
- Möbius Function
- 0
- Radical
- 42
- Omega Function (Ω)
- 7
- 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
- yes
- Harshad Number
- yes
- Narcissistic Number
- no
- Collatz Steps
- 145
- 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
- Coefficients of Legendre polynomials.at n=5A002462
- Coordination sequence for NiAs(2), As position.at n=42A009945
- a(0) = 1, a(n) = 31*n^2 + 2 for n>0.at n=16A010020
- Expansion of e.g.f. 1/sqrt(exp(x)*(2-exp(x))).at n=7A014304
- Numbers k such that k divides 2^(k+1) - 2.at n=30A014741
- Positive integers n such that n | (2^n + n/2 - 1).at n=28A015942
- a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n+1-k), where k = [ (n+1)/2 ], s = (odd natural numbers), t = (primes).at n=23A024603
- a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (odd natural numbers), t = (primes).at n=22A025117
- Unbalanced strings of length n.at n=13A027556
- Number of forests of rooted trees where n dollars are spent and an n-node tree costs 2n-1 dollars.at n=21A038000
- Triangular matrix arising in enumeration of catafusenes, read by rows.at n=41A038763
- Numbers n such that A048767(n) = n.at n=25A048768
- A convolution triangle of numbers generalizing Pascal's triangle A007318.at n=60A049324
- a(0)=4, a(1)=0, a(2)=0, a(3)=3; thereafter a(n) = a(n-3) + a(n-4).at n=45A050443
- Numbers n such that n^3 is the sum of two nonzero squares in exactly one way.at n=37A050804
- An approximation to sigma_{5/2}(n): floor( sum_{d|n} d^(5/2) ).at n=33A058272
- Smallest m such that A065623(m) = n.at n=18A065624
- Numbers k that divide phi(k)*bigomega(k).at n=42A067575
- Number of basis partitions of n+81 with Durfee square size 9.at n=21A069252
- Numbers k such that the sum of exponents of k is equal to the greatest prime factor of k; a(1)=1.at n=43A071929