12215
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 11
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 16800
- Proper Divisor Sum (Aliquot Sum)
- 4585
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 8352
- Möbius Function
- -1
- Radical
- 12215
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 156
- 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
- Number of partitions of n such that cn(0,5) = cn(2,5) < cn(3,5) = cn(4,5) < cn(1,5).at n=64A036858
- Gaps of 7 in sequence A038593 (lower terms).at n=32A038653
- Numbers ending with '5' that are the difference of two positive cubes.at n=33A038860
- a(n) = (n+5)^3 - n^3.at n=26A038867
- Number of simple class-1 graphs on n nodes.at n=7A099435
- sigma(n)-phi(n) and sigma(n)+phi(n) are two palindromes greater than 2.at n=5A116031
- Numbers such that the digital sum base 2 and the digital sum base 3 and the digital sum base 10 all are equal.at n=13A135120
- Triangle T(n, k, m) = coefficients of p(x, n, m) where p(x,n,m) = (x+1)*p(x, n-1, m) + (2^(m+n-1) + 2^(n-2)*[n>=3])*x*p(x, n-2, m) and m=2, read by rows.at n=23A154984
- Triangle T(n, k, m) = coefficients of p(x, n, m) where p(x,n,m) = (x+1)*p(x, n-1, m) + (2^(m+n-1) + 2^(n-2)*[n>=3])*x*p(x, n-2, m) and m=2, read by rows.at n=25A154984
- Numbers n such that 15*prime(n)+{-4,-2,2,4} are all primes.at n=30A176002
- Expansion of Sum_{i>=1} x^(i*(i+1)/2)/(1 - x^(i*(i+1)/2)) / Product_{j>=1} (1 - x^(j*(j+1)/2)).at n=55A281615
- a(0)=1; thereafter a(n) = Sum_{k=2..n+1} A006206(k).at n=23A286271