2101
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 4
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 2304
- Proper Divisor Sum (Aliquot Sum)
- 203
- 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
- 1900
- Möbius Function
- 1
- Radical
- 2101
- 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
- 32
- 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
- a(n) = n^2 written in base 3.at n=8A001738
- Squares written in base 8.at n=32A002441
- Number of connected 2-plexes.at n=5A003190
- Cubes written in base 3.at n=3A004633
- Powers of 2 written in base 3.at n=6A004642
- a(n) = 5^n - 4^n.at n=5A005060
- Numbers k such that k, k+1 and k+2 have the same number of divisors.at n=40A005238
- Weighted count of partitions with odd parts.at n=32A005896
- Pseudoprimes to base 7.at n=8A005938
- Numbers k for which 10k+1, 10k+3, 10k+7 and 10k+9 are primes.at n=18A007811
- Expansion of (1+x^2)(1+x^4)/((1-x)^2*(1-x^2)*(1-x^3)).at n=26A007979
- Coordination sequence T4 for Zeolite Code BRE.at n=30A008061
- Coordination sequence T3 for Zeolite Code MTT.at n=28A008191
- Expansion of (1+x^8)/((1-x)*(1-x^2)*(1-x^3)*(1-x^4)).at n=52A008769
- Representation of n in base of Catalan numbers (a classic greedy version).at n=34A014418
- a(n) = (1 - (-7)^n)/8.at n=4A014989
- Triangle of q-binomial coefficients for q=-7.at n=16A015117
- Triangle of q-binomial coefficients for q=-7.at n=19A015117
- Gaussian binomial coefficient [ n,4 ] for q = -7.at n=1A015293
- a(n) = 6*a(n-1) + 7*a(n-2), a(0) = 0, a(1) = 1.at n=5A015552