12005
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 8
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 10
- Divisor Sum
- 16806
- Proper Divisor Sum (Aliquot Sum)
- 4801
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 8232
- Möbius Function
- 0
- Radical
- 35
- 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
- 42
- 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
- no
- Odd
- yes
Appears in sequences
- Numbers of the form 5^i*7^j with i, j >= 0.at n=19A003595
- Triangle of coefficients in expansion of (1+7x)^n.at n=31A013614
- Triangle of coefficients in expansion of (1+7x)^n.at n=19A013614
- Numbers k that divide s(k), where s(1)=1, s(j)=15*s(j-1)+j.at n=41A014865
- Triangle whose (i,j)-th entry is binomial(i,j)*7^(i-j).at n=16A027466
- Triangle whose (i,j)-th entry is binomial(i,j)*7^(i-j).at n=32A027466
- Second column of A027466.at n=4A027473
- a(n) = 5*n^2.at n=49A033429
- Numbers whose prime factors are 5 and 7.at n=9A033851
- Composite numbers whose prime factors contain no digits other than 5 and 7.at n=22A036320
- Numbers whose prime factors are in {5, 7, 11}.at n=39A036490
- Duplicate of A027466.at n=16A038267
- Numbers whose base-7 representation contains exactly four 0's.at n=4A043396
- Odd numbers with only palindromic prime factors whose sum is palindromic (counted with multiplicity).at n=34A046356
- Odd numbers with exactly 5 palindromic prime factors (counted with multiplicity).at n=38A046375
- Numbers n such that n | 9^n + 8^n + 7^n + 6^n + 5^n.at n=22A057253
- Numbers k that can be expressed as k = w+x = y*z with w*x = (y+z)^3 where w, x, y, and z are all positive integers.at n=18A057370
- For the numbers k that can be expressed as k = w + x = y*z with w*x = y^3 + z^3 where w, x, y, and z are all positive integers, this sequence gives the corresponding values of w*x.at n=7A057443
- Numbers k that divide 8^k + 7^k + 6^k + 5^k + 4^k + 3^k + 2^k.at n=30A057490
- Triangular array T(n,k) read by rows, giving number of rooted trees on the vertex set {1..n+1} where k children of the root have a label smaller than the label of the root.at n=32A071207