10890
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 36
- Divisor Sum
- 31122
- Proper Divisor Sum (Aliquot Sum)
- 20232
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 2640
- Möbius Function
- 0
- Radical
- 330
- Omega Function (Ω)
- 6
- Little Omega Function (ω)
- 4
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
- 55
- 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
- Let j = | i - i_written_backwards |, k = j + j_written_backwards; then k is in this sequence.at n=42A008920
- Numbers k such that k and 9*k are anagrams.at n=4A023093
- a(n) = 2*(n+1)*binomial(n+2,4).at n=8A027777
- a(n) = 9*(n+1)*binomial(n+2,9)/2.at n=3A027782
- a(n) = 10*n^2.at n=33A033583
- Trajectory of 9 under map x->x + (x-with-digits-reversed).at n=5A033651
- Trajectory of 27 under map x->x + (x-with-digits-reversed).at n=4A033659
- Trajectory of 99 under map x->x + (x-with-digits-reversed).at n=3A033674
- Theta series of lattice A_2 tensor D_3 (dimension 6, det. 432, min. norm 4).at n=36A033701
- Differences of A038011.at n=11A038012
- T(n,n-2), array T as in A038792.at n=8A038737
- T(n+4,n), array T as in A038792.at n=8A038797
- Numerators of continued fraction convergents to sqrt(910).at n=2A042758
- Number of nonempty subsets of {1,2,...,n} in which exactly 1/6 of the elements are <= (n-1)/2.at n=21A047180
- Number of nonempty subsets of {1,2,...,n} in which exactly 1/6 of the elements are <= (n-2)/2.at n=21A047191
- a(n) = n^2*(n-1)*(n-2).at n=9A047929
- Numbers for which reduced residue system contains as many primes as nonprimes.at n=28A048869
- a(n) = n^2 + (n^2 with digits reversed).at n=33A061226
- Write 1, 2, 3, 4, ... counterclockwise in a hexagonal spiral around 0 starting left down, then a(n) is the sequence found by reading from 0 in the vertical upward direction.at n=30A063436
- Eighth column of quintinomial coefficients.at n=8A064057