15069
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 20096
- Proper Divisor Sum (Aliquot Sum)
- 5027
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 10044
- Möbius Function
- 1
- Radical
- 15069
- Omega Function (Ω)
- 2
- 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
- 89
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
- no
- Odd
- yes
Appears in sequences
- Apply partial sum operator twice to binary rooted tree numbers.at n=15A014168
- Discriminants of real quadratic fields with class number 1 and related continued fraction period length of 22.at n=43A051963
- Largest eigenvalue, rounded to the nearest integer, of a rank n matrix of 1..n^2 filled successively along rows.at n=30A072333
- a(n) = sigma_3(n) - sigma_2(n) - sigma_1(n).at n=24A092350
- Numbers k such that k^4 contains a pandigital substring.at n=29A115934
- Triangle T(n, k) = T(n-1, k) + T(n-1, k-1) + (2*j +3)*prime(j)*T(n-2, k-1) with j=9, read by rows.at n=22A153656
- Triangle T(n, k) = T(n-1, k) + T(n-1, k-1) + (2*j +3)*prime(j)*T(n-2, k-1) with j=9, read by rows.at n=26A153656
- Number of indecomposable permutations sortable by a double-ended queue.at n=8A215257
- Numbers n such that 8^n-7^(n-1) is prime.at n=10A272345
- a(n) is the number of integer partitions of n for which the greatest part minus the least part is equal to the index of the seaweed algebra formed by the integer partition paired with its weight.at n=53A318176
- Expansion of Product_{k>=1} 1/(1 - phi(k)*x^k), where phi = Euler totient function (A000010).at n=20A319111
- Self-convolution of n-th antidiagonal of the natural number array (so named in the Comments section of A000027).at n=8A387429
- a(n) = Sum_{k=0..floor(n/3)} 2^k * binomial(2*n-4*k,2*k).at n=12A387622