3956
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 23
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 7392
- Proper Divisor Sum (Aliquot Sum)
- 3436
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 1848
- Möbius Function
- 0
- Radical
- 1978
- Omega Function (Ω)
- 4
- 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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 51
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- 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
- Generating function = Product_{m>=1} 1/(1 - x^m)^2; a(n) = number of partitions of n into parts of 2 kinds.at n=15A000712
- Coordination sequence T7 for Zeolite Code PAU.at n=46A008225
- Coordination sequence T1 for Keatite.at n=35A009844
- Numbers k such that the geometric mean of phi(k) and sigma(k) is an integer.at n=43A011257
- Apply partial sum operator thrice to partition numbers.at n=13A014160
- a(n) is the least multiple of n, k*n say, such that phi(k) | sigma(k).at n=45A015756
- a(n) is the least multiple of n, k*n say, such that phi(k) | sigma(k).at n=22A015756
- Powers of cube root of 12 rounded down.at n=10A018009
- Powers of cube root of 12 rounded to nearest integer.at n=10A018010
- Nearest integer to Gamma(n + 10/11)/Gamma(10/11).at n=7A020005
- Ceiling of Gamma(n+10/11)/Gamma(10/11).at n=7A020095
- Numbers k such that d(k) (number of divisors) divides phi(k) (Euler function) divides sigma(k) (sum of divisors).at n=40A020493
- a(n) = n*(15*n - 1)/2.at n=23A022272
- a(n) = position of 3*(n^2) in A000408.at n=39A024800
- Numbers k such that phi(k)*d(k) is a multiple of sigma(k), where d(k) is the number of divisors of k.at n=22A050934
- Sum of a(n) terms of 1/k^(2/3) first exceeds n.at n=45A056178
- Numbers k such that 2^k + 21 is prime.at n=28A057201
- Dimension of the space of weight n cuspidal newforms for Gamma_1( 87 ).at n=19A063360
- Numbers k such that k and k+1 have the same sum of unitary divisors (A034448).at n=15A064125
- Numbers k such that sigma(k) divides k*phi(k).at n=45A066995