1305
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 9
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 2340
- Proper Divisor Sum (Aliquot Sum)
- 1035
- 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
- 672
- Möbius Function
- 0
- Radical
- 435
- Omega Function (Ω)
- 4
- 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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 52
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- 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
- Let A(n) = #{(i,j): i^2 + j^2 <= n}, V(n) = Pi*n, P(n) = A(n) - V(n); A000099 gives values of n where |P(n)| sets a new record; sequence gives A(A000099(n)).at n=15A000323
- Expansion of g.f. (1 + x + 2*x^2)/((1 - x)^2*(1 - x^3)).at n=43A000969
- Number of graphs with n nodes and n-2 edges.at n=10A001430
- MacMahon's generalized sum of divisors function.at n=19A002127
- Numbers k such that 9*2^k + 1 is prime.at n=22A002256
- Numbers that are the sum of 10 positive 6th powers.at n=20A003366
- Number of paraffins.at n=16A005997
- E.g.f.: 1/(1-x*exp(x)).at n=5A006153
- Coordination sequence T1 for Zeolite Code APC.at n=25A008032
- Coordination sequence T1 for Zeolite Code LTN.at n=25A008140
- Coordination sequence T11 for Zeolite Code MFI.at n=23A008163
- Expansion of (1+x^10)/((1-x)*(1-x^2)*(1-x^3)*(1-x^4)).at n=45A008771
- Coordination sequence T2 for Zeolite Code -ROG.at n=27A009860
- Pseudoprimes to base 17.at n=11A020145
- Pseudoprimes to base 28.at n=13A020156
- Pseudoprimes to base 46.at n=20A020174
- a(n) is least k such that k and 9k are anagrams in base n (written in base 10).at n=20A023101
- Denominator of n*(n-3)*(3*n^2 - 6*n + 2)/(3*(n-1)*(n-2)).at n=28A023418
- s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n+1-k), where k = [ (n+1)/2 ], s = A023532, t = (odd natural numbers).at n=46A024372
- Positions of nonprimes among the powers of primes (A000961).at n=52A024621