2451
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 12
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 3520
- Proper Divisor Sum (Aliquot Sum)
- 1069
- 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
- 1512
- Möbius Function
- -1
- Radical
- 2451
- Omega Function (Ω)
- 3
- Little Omega Function (ω)
- 3
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
- 133
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- 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
- From a differential equation.at n=8A000998
- a(n) = sigma_2(n): sum of squares of divisors of n.at n=48A001157
- Genus of modular group Gamma(n) = genus of modular curve Chi(n).at n=39A001767
- Expansion of (1+x^3)/((1-x)*(1-x^2)^2*(1-x^3)).at n=42A001973
- Central polygonal numbers: a(n) = n^2 - n + 1.at n=50A002061
- Numbers that are the sum of 11 positive 7th powers.at n=14A003378
- Number of nonequivalent dissections of an n-gon into 3 polygons by nonintersecting diagonals up to rotation and reflection.at n=35A003453
- Number of strict 3rd-order maximal independent sets in path graph.at n=36A007384
- Coordination sequence T1 for Zeolite Code DDR.at n=31A008071
- Coordination sequence T1 for Zeolite Code ERI and OFF.at n=36A008093
- Coordination sequence T2 for Zeolite Code -ROG.at n=37A009860
- a(n) = floor( n*(n-1)*(n-2)/11 ).at n=31A011893
- [ n(n-1)(n-2)(n-3)/7 ].at n=13A011917
- Numbers n such that phi(n) * sigma(n) + 9 is a perfect square.at n=30A015728
- Numerator of sum of -2nd powers of divisors of n.at n=48A017667
- Expansion of 1/(1-x^3-x^4-x^5-x^6-x^7-x^8-x^9-x^10-x^11).at n=25A017824
- Pseudoprimes to base 94.at n=28A020222
- Least k such that first k terms of A022300 contain n more 1's than 2's.at n=14A022302
- Sum of the products of the primes taken 2 at a time from the first n primes.at n=7A024447
- a(n) = least m such that if r and s in {1/2, 1/4, 1/6,..., 1/2n} satisfy r < s, then r < k/m < s for some integer k.at n=39A024820