7908
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
- 1
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 18480
- Proper Divisor Sum (Aliquot Sum)
- 10572
- 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
- 2632
- Möbius Function
- 0
- Radical
- 3954
- Omega Function (Ω)
- 4
- 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
- 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
- Number of partitions of n into parts not of the form 25k, 25k+4 or 25k-4. Also number of partitions with at most 3 parts of size 1 and differences between parts at distance 11 are greater than 1.at n=34A036003
- Numbers k such that 2^k - 23 is prime.at n=16A057220
- Factorable subsets: the number of proper subsets S of {1,2,...,n} that can be expressed in the form S=A*B, where S is defined to be the set {a(i)*b(j)| a(i) in A, b(j) in B}.at n=24A068594
- Numbers n such that n and the n-th prime have the same digits.at n=23A074350
- Number of permutations of length n which avoid the patterns 1234, 2431, 4132.at n=9A116835
- Triangle of coefficients of characteristic polynomials of anti-symmetrical tridiagonal matrices: Middle diagonal: a=1; Lower first subdiagonal: b=2; Upper first subdiagonal: c=-2; Example: M(3) {{1, -2, 0}, {2, 1, -2}, {0, 2, 1}}.at n=47A136643
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (-1, -1, 1), (0, 0, -1), (0, 1, 0), (1, 1, 1)}.at n=7A150594
- Sum of first n isolated (or single) primes A007510.at n=36A153478
- Hilbert series related to measurement of quantum entanglement - see Hero and Willenbring for precise definition.at n=4A176626
- Initial members of abundant quadruplets, i.e., values of k such that (k, k+2, k+4, k+6) are all abundant numbers.at n=17A231089
- Consecutive exclusionary squares: Numbers n such that n^2 does not contain digits of n and (n+1)^2 does not contain digits of n+1.at n=45A247843
- T(n,k) = Number of n X k arrays containing k copies of 0..n-1 with no element 1 greater than its north or southwest neighbor modulo n and the upper left element equal to 0.at n=38A266861
- Number of 3Xn arrays containing n copies of 0..3-1 with no element 1 greater than its north or southwest neighbor modulo 3 and the upper left element equal to 0.at n=6A266862
- T(n,k)=Number of nXk arrays containing k copies of 0..n-1 with every element equal to or 1 greater than any north or southwest neighbors modulo n and the upper left element equal to 0.at n=38A267655
- p-INVERT of the even positive integers (A005843), where p(S) = 1 - S - S^2.at n=5A289787
- The first Zagreb index of the Aztec diamond AZ(n) (see the Ramanes et al. reference, Theorem 2.1).at n=14A292344
- Number of nX5 0..1 arrays with every element equal to 0, 1, 4 or 5 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.at n=10A302512
- Number of series-reduced connected labeled graphs with n edges.at n=7A331584
- Sum of the areas of all r X s rectangles such that r < s, r + s = 2n and (s - r) | (s * r).at n=35A333754
- a(n) = Sum_{j=1..n} Sum_{k=1..n} phi(n*j*k) / phi(n*k).at n=25A372669