2231
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 8
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 2352
- Proper Divisor Sum (Aliquot Sum)
- 121
- 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
- 2112
- Möbius Function
- 1
- Radical
- 2231
- 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
- 94
- 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
- Ramanujan's approximation to population of x^2 + y^2 <= 2^n.at n=13A000691
- Primes written in base 4.at n=39A004678
- Odd numbers not of form p + 2^k (de Polignac numbers).at n=50A006285
- Number of loopless rooted planar maps with 3 faces and n vertices and no isthmuses. Also a(n)=T(4,n-3), array T as in A049600.at n=20A006416
- Coordination sequence T2 for Zeolite Code EPI.at n=30A008091
- Coordination sequence T9 for Zeolite Code EUO.at n=29A008104
- Coordination sequence T4 for Zeolite Code HEU.at n=31A008119
- Super-3 Numbers (3n^3 contains substring '333' in its decimal expansion).at n=16A014569
- n-th composite is sum of first k composites for some k.at n=46A020642
- Index of 10^n within the sequence of the numbers of the form 2^i*10^j.at n=36A025740
- Numbers k that divide the (left) concatenation of all numbers <= k written in base 8 (most significant digit on left).at n=12A029477
- The "semi-Fibonacci numbers": a(n) = A030067(2n - 1), where A030067 is the semi-Fibonacci sequence.at n=53A030068
- 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 47.at n=2A031545
- Numbers that, when expressed in base 2 and then interpreted in base 10, yield a multiple of the original number.at n=38A032533
- Odd numbers that, when expressed in base 2 and then interpreted in base 10, yield a multiple of the original number.at n=3A032535
- Concatenation of n and n + 9 or {n,n+9}.at n=21A032614
- Coordination sequence T1 for Zeolite Code SBE.at n=38A033604
- A summarize Fibonacci sequence starting with a(0)=1 and a(1)=2: summarize the previous two terms!.at n=3A036106
- Growth function (or coordination sequence) of the infinite cubic graph corresponding to the srs net (a(n) = number of nodes at distance n from a fixed node).at n=41A038620
- Denominators of continued fraction convergents to sqrt(92).at n=8A041165