10981
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 11200
- Proper Divisor Sum (Aliquot Sum)
- 219
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 10764
- Möbius Function
- 1
- Radical
- 10981
- Omega Function (Ω)
- 2
- Little Omega Function (ω)
- 2
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
- 42
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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 series-reduced trees with n nodes.at n=22A000014
- Coordination sequence for MgNi2, Position Mg2.at n=26A009935
- An "extremely strange sequence": a(n+1) = [ A*a(n)+B ]/p^r, where p^r is the highest power of p dividing [ A*a(n)+B ] and p=2, A=4.001, B=1.2.at n=25A028948
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 66 ones.at n=10A031834
- Number of partitions in parts not of the form 13k, 13k+1 or 13k-1. Also number of partitions with no part of size 1 and differences between parts at distance 5 are greater than 1.at n=45A035949
- Number of partitions of n into parts not of the form 13k, 13k+6 or 13k-6. Also number of partitions with at most 5 parts of size 1 and differences between parts at distance 5 are greater than 1.at n=38A035954
- Numbers ending with '1' that are the difference of two positive cubes.at n=38A038856
- Denominators of continued fraction convergents to sqrt(322).at n=6A041609
- Indices of pentagonal numbers which are also 9-gonal.at n=2A048914
- Composite numbers whose divisors (except 1) all contain the digit 9.at n=18A062680
- Period of the Lucas 3-step sequence A001644 mod prime(n).at n=41A106294
- Period of the Fibonacci 3-step sequence A000073 mod prime(n).at n=41A106302
- Semiprimes in A003215.at n=23A113530
- Largest number k such that k^2 divides A007781(6n+1).at n=29A127854
- Reduced period of the Fibonacci 3-step sequence A000073 mod prime(n).at n=41A154753
- a(n) = 289*n - 1.at n=37A158253
- a(n) = 38*n^2 - 1.at n=16A158596
- Cuban composites: composite numbers equal to the difference of two consecutive cubes.at n=30A159961
- Triangle read by rows: T(n,k) is the number of ordered trees with n edges and having k vertices of outdegree 2 that have (two) leaves as their (two) children.at n=23A178519
- Number of ordered trees with n edges and with no vertex of outdegree 2 that have two leaves as their two children.at n=10A178520