2153
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 11
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 2154
- Proper Divisor Sum (Aliquot Sum)
- 1
- 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
- 2152
- Möbius Function
- -1
- Radical
- 2153
- Omega Function (Ω)
- 1
- Little Omega Function (ω)
- 1
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
- 76
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- yes
- Composite Number
- no
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 325
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Numbers k such that phi(2k-1) < phi(2k), where phi is Euler's totient function A000010.at n=30A001836
- Positions of remoteness 5 in Beans-Don't-Talk.at n=47A005697
- a(n) = (5*n + 1)^2 + 4*n + 1.at n=9A007533
- Coordination sequence T1 for Zeolite Code AFI.at n=32A008014
- Coordination sequence T1 for Zeolite Code LAU.at n=33A008124
- If a, b in sequence, so is ab+7.at n=22A009312
- a(n) = prime(n*(n+1)/2).at n=24A011756
- Numbers k such that the continued fraction for sqrt(k) has period 3.at n=11A013643
- Primes that remain prime through 2 iterations of function f(x) = 9x + 2.at n=33A023265
- Expansion of Molien series for 8-dimensional real Clifford group 2^{1+6}.Alt_8.2 of genus 3 and order 5160960.at n=36A024186
- a(n) = Sum_{k=0..n-1} T(n,k) * T(n,2n-k), with T given by A027113.at n=5A027136
- Squarefree n such that Q(sqrt(n)) has class number 5.at n=17A029705
- a(n) = prime(8*n-3).at n=40A031389
- a(n) = prime(10*n - 5).at n=32A031910
- a(n) = prime(9*n-8).at n=36A031918
- Lower prime of a difference of 8 between consecutive primes.at n=27A031926
- Upper prime of a difference of 10 between consecutive primes.at n=33A031929
- Primes of form x^2+31*y^2.at n=49A033221
- Primes of form x^2+41*y^2.at n=15A033228
- Primes of form x^2+89*y^2.at n=7A033257