2865
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 4608
- Proper Divisor Sum (Aliquot Sum)
- 1743
- 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
- 1520
- Möbius Function
- -1
- Radical
- 2865
- 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
- 27
- 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
- For any circular arrangement of 0..n-1, let S = sum of squares of every sum of two contiguous numbers; then a(n) = # of distinct values of S.at n=25A007773
- Coordination sequence T1 for Zeolite Code AFS.at n=41A008023
- Coordination sequence T2 for Zeolite Code LTN.at n=37A008141
- Coordination sequence T6 for Zeolite Code MFS.at n=33A008178
- Coordination sequence T1 for Zeolite Code CGF.at n=37A019451
- Number of 8's in all partitions of n.at n=33A024792
- a(n) = position of 3*n^2 in sequence A025051 (numbers of form j*k + k*i + i*j, without repetitions, where 1 <= i <= j <= k).at n=30A025056
- a(n) = [ Sum{(log(j)-log(i))^3} ], 2 <= i < j <= n.at n=48A025207
- Number of partitions of n in which the least part is even.at n=36A026805
- Positive numbers having the same set of digits in base 6 and base 7.at n=38A033170
- Coordination sequence T4 for Zeolite Code SBE.at n=43A033607
- Number of connected numbers (A029827) with binary order (A029837) <= n.at n=13A036387
- Numbers having three 3's in base 9.at n=26A043467
- Number of tilings of 2 X n rectangle with polyominoes, each of which has area = # of adjacent polyominoes.at n=15A044043
- Numbers n such that string 3,3 occurs in the base 9 representation of n but not of n-1.at n=35A044281
- Numbers n such that string 6,5 occurs in the base 10 representation of n but not of n-1.at n=31A044397
- Numbers n such that string 3,3 occurs in the base 9 representation of n but not of n+1.at n=35A044662
- Numbers n such that string 6,5 occurs in the base 10 representation of n but not of n+1.at n=31A044778
- Numbers of the form p*q*r where p,q,r are (not necessarily distinct) odd palindromic primes (odd terms from A002385).at n=33A046373
- Numbers with exactly 3 distinct palindromic prime factors.at n=36A046401