2156
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 14
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 18
- Divisor Sum
- 4788
- Proper Divisor Sum (Aliquot Sum)
- 2632
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 840
- Möbius Function
- 0
- Radical
- 154
- Omega Function (Ω)
- 5
- 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
- 50
- 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
- Self numbers divisible by sum of their digits (or, self numbers which are also Harshad numbers).at n=47A003219
- a(n) = least integer m > a(n-1) such that m - a(n-1) != a(j) - a(k) for all j, k less than n; a(1) = 1, a(2) = 2.at n=44A004978
- Coordination sequence T2 for Zeolite Code BOG.at n=33A008050
- Coordination sequence T3 for Zeolite Code BOG.at n=33A008051
- Expansion of 1/((1-x)^2*(1-x^2)*(1-x^4)).at n=43A008804
- Coordination sequence T2 for Zeolite Code -ROG.at n=35A009860
- Coordination sequence for Ni2In, Position Ni2.at n=14A009942
- Positive numbers k such that k and 3*k are anagrams in base 8 (written in base 8).at n=2A023074
- Numbers k such that Fibonacci(k) == -3 (mod k).at n=29A023164
- a(n) = Sum_{k=1..n} floor((n/k)*floor(n/k)).at n=36A024921
- a(n) = n*(n+5).at n=44A028557
- Numbers n such that n divides the (left) concatenation of all numbers <= n written in base 23 (most significant digit on right and removing all least significant zeros before concatenation).at n=6A029540
- a(n+1) = Sum_{k=0..floor(n/5)} a(k) * a(n-k).at n=18A030036
- Numbers with 18 divisors.at n=35A030636
- 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 22.at n=38A031520
- a(n) = 11*n^2.at n=14A033584
- Coordination sequence T3 for Zeolite Code AFN.at n=33A038401
- Numbers n such that string 0,0 occurs in the base 7 representation of n but not of n-1.at n=43A044138
- Numbers n such that string 5,4 occurs in the base 8 representation of n but not of n-1.at n=37A044231
- Numbers n such that string 5,5 occurs in the base 9 representation of n but not of n-1.at n=26A044301