15211
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 10
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 18144
- Proper Divisor Sum (Aliquot Sum)
- 2933
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 12480
- Möbius Function
- -1
- Radical
- 15211
- Omega Function (Ω)
- 3
- 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
- no
- Narcissistic Number
- no
- Collatz Steps
- 71
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- 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
- Deceptive nonprimes: composite numbers k that divide the repunit R_{k-1}.at n=26A000864
- Pseudoprimes to base 10.at n=42A005939
- Pseudoprimes to base 66.at n=35A020194
- Pseudoprimes to base 78.at n=33A020206
- Strong pseudoprimes to base 40.at n=18A020266
- Strong pseudoprimes to base 100.at n=27A020326
- a(n) = (2*n+1)*(11*n+1).at n=26A033575
- Numbers whose product of decimal digits equals its sum of binary digits.at n=27A064003
- Nonprimes whose sum of digits is equal to its product of digits.at n=39A066307
- Take the list t(n,0) = {1,...,n}; denote by t(n,j) this list after rotating to left (or right) by j positions. Calculate inner product of t(n,0) and t(n,j) and denote the value by s(n,j). Compute this inner product for all j = 1..n and choose the smallest. This is a(n).at n=40A088003
- a(n) = n*(9*n+2).at n=41A147296
- 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, 0, 1), (-1, 1, 0), (1, -1, -1), (1, 1, 0)}.at n=9A149096
- Numbers k such that (sum of base-2 digits of k) = (sum of base-10 digits of k) = 10.at n=26A152207
- a(n) = 10*n^2 + 1.at n=39A158187
- A three-dimensional version of the cellular automaton A160118, using cubes.at n=16A160119
- Numbers k such that 2^(2k-1) == 2 (mod 2k) and such that 2^(k-1) != 1 (mod k).at n=30A176033
- Numbers with digital product = 10.at n=31A199990
- Composite numbers whose product of digits is 10.at n=26A201057
- Number of partitions of n in which any two parts differ by at most 7.at n=43A218509
- Numbers n such that 3^9*2^n - 1 is prime.at n=26A231374