1930
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 3492
- Proper Divisor Sum (Aliquot Sum)
- 1562
- 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
- 768
- Möbius Function
- -1
- Radical
- 1930
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 24
- 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
- yes
- Odd
- no
Appears in sequences
- Let A(n) = #{(i,j,k): i^2 + j^2 + k^2 <= n}, V(n) = (4/3)Pi*n^(3/2), P(n) = A(n) - V(n); A000092 gives values of n where |P(n)| sets a new record; sequence gives (nearest integer to, I believe) P(A000092(n)).at n=41A000223
- Number of pairs of consecutive integers x, x+1 such that all prime factors of both x and x+1 are at most the n-th prime.at n=15A002071
- a(n) is the number of alpha-labelings of graphs with n edges.at n=7A005193
- Number of equivalence classes of 4 X n binary matrices when one can permute rows, permute columns and complement columns.at n=11A006380
- Coordination sequence T2 for Zeolite Code EAB and OFF.at n=32A008083
- Molien series for A_11.at n=26A008634
- Number of partitions of n into at most 11 parts.at n=26A008640
- Coordination sequence T3 for Zeolite Code -ROG.at n=33A009861
- Coordination sequence for MgCu2, Mg position.at n=11A009931
- Coefficients in expansion of sqrt(2) as Sum_{n>=1} a(n)/(n*n!*(n+1)!), as found by greedy algorithm.at n=46A011193
- Numbers k such that the continued fraction for sqrt(k) has period 13.at n=12A020352
- Place where n-th 1 occurs in A023123.at n=37A022785
- Numbers k such that Fibonacci(k) == -55 (mod k).at n=36A023170
- Base 6 expansion uses each positive digit just once.at n=4A023744
- a(n) = Sum_{k=1..n} k*floor(n/k); also Sum_{k=1..n} sigma(k) where sigma(n) = sum of divisors of n (A000203).at n=47A024916
- a(n) = n-th largest even number in array T given by A027170.at n=33A027183
- a(n) = (n+3)^2 - 6.at n=41A028878
- Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted then there are a pair of central terms both equal to 9.at n=2A031422
- a(n)/4^n is the expected number of tosses of a coin required to obtain n+1 heads or n+1 tails.at n=4A033504
- Upper of pair of consecutive happy numbers.at n=43A035503