15951
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- yes
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 22960
- Proper Divisor Sum (Aliquot Sum)
- 7009
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 9792
- Möbius Function
- -1
- Radical
- 15951
- 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
- 146
- 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
- Molien series for alternating group Alt_8 (or A_8).at n=44A008631
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 84.at n=30A031582
- a(n) = smallest palindrome > a(n-1) such that a(1)*a(2)*...*a(n) - 1 is a prime.at n=26A051954
- Difference between average of smallest prime greater than n^3 and largest prime less than (n+1)^3 and n-th pronic [=n(n+1)].at n=23A063036
- Palindromic odd composite numbers that are the products of an odd number of distinct primes.at n=33A075808
- Subdiagonal of array of n-gonal numbers A081422.at n=25A081423
- a(n) is the odd-length palindrome whose digits up to the center are those of n and whose center digit is equal to the digital root of the product of the factorial of n and the reverse of n.at n=14A082941
- Palindromes with more than 3 digits in which the absolute difference of a pair of successive digits is identical.at n=18A085109
- Palindromic in bases 10 and 32.at n=22A099165
- Palindromes n such that 10n01 is a prime.at n=26A099744
- Consider all (2n+1)-digit palindromic primes of the form 10...0M0...01 (so that M is a palindrome with <= 2n-1 digits); a(n) = smallest such M.at n=55A100026
- Consider all (2n+1)-digit palindromic primes of the form 70...0M0...07 (so that M is a palindrome with <= 2n-1 digits); a(n) = smallest such M.at n=42A100956
- a(0)=1, a(1)=1, a(n) = 11*a(n/2) for even n, and a(n) = 10*a((n-1)/2) + a((n+1)/2) for odd n >= 3.at n=21A116525
- Palindromic mountain numbers.at n=30A173070
- Triangle, read by rows, equal to the matrix cube of triangle A185620.at n=28A185628
- Column 0 of triangle A185628; also, equals row sums of triangle A185624.at n=7A185629
- Number of 0..n arrays x(0..3) of 4 elements without any two consecutive increases.at n=10A200786
- Number of (w,x,y,z) with all terms in {1,...,n} and 3w=x+y+z+n+2.at n=39A212252
- Happy palindromic numbers.at n=36A216237
- Numbers k such that antisigma(k) mod k = antisigma(k+1) mod (k+1).at n=7A229114