15206
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 14
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 22812
- Proper Divisor Sum (Aliquot Sum)
- 7606
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 7602
- Möbius Function
- 1
- Radical
- 15206
- 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
- 32
- 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
- yes
- Odd
- no
Appears in sequences
- a(n) = Sum_{k=n..2*n} T(n,k), T given by A027052.at n=10A027067
- Numbers whose base-7 representation contains exactly four 2's.at n=29A043404
- Numbers k such that 4*10^k + 3*R_k is prime, where R_k = 11...1 is the repunit (A002275) of length k.at n=17A056707
- Triangle read by rows: T(n,k) is number of Dyck paths of semilength n having k ascents of length 1 starting at an even level.at n=68A102404
- a(n) = floor((x^n - (1-x)^n)/sqrt(2)+ 1/2) where x = (sqrt(2)+1)/2.at n=52A136421
- Number of cycles of length 4 in the queen graph associated with an n X n chessboard.at n=7A156001
- Least numbers k for each base b >= 2 such that N = b^(2^n) + k is prime for 6 consecutive values from n = 0 to n = 5.at n=19A225492
- The n-th number m such that a nontrivial prime(n)-th root of unity modulo m exists.at n=41A305828
- G.f. A(x) satisfies A(x) = (1 + x*A(x) / (1+x))^5.at n=5A371544
- Triangle read by rows: Trace of the Akiyama-Tanigawa algorithm for powers x^3.at n=29A371764
- a(n) = A371764(n, 2).at n=6A372148
- Number of forests with at most n unlabeled nodes.at n=14A386399