1971
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 2960
- Proper Divisor Sum (Aliquot Sum)
- 989
- 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
- 1296
- Möbius Function
- 0
- Radical
- 219
- Omega Function (Ω)
- 4
- 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
- 24
- 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
- Numbers that are the sum of 11 positive 6th powers.at n=31A003367
- Divisors of 2^18 - 1.at n=21A003528
- For any circular arrangement of 0..n-1, let S = sum of squares of every sum of two contiguous numbers; then a(n) = # of distinct values of S.at n=22A007773
- Coordination sequence T2 for Zeolite Code CAS.at n=27A008064
- Coordination sequence T1 for Zeolite Code AHT.at n=30A009866
- a(n) = floor(n*(n-1)*(n-2)/7).at n=25A011889
- Numbers k such that k divides 4^k - 1.at n=22A014945
- Positive integers n such that 2^n (mod n) == 2^9 (mod n).at n=77A015931
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly five 1's.at n=17A020441
- a(n) = (d(n)-r(n))/5, where d = A026049 and r is the periodic sequence with fundamental period (4,1,4,0,1).at n=26A026051
- Size of lexicographic code of length n, Hamming distance 10 and weight 10.at n=30A031502
- Number of dyslexic identity planted planar trees with n+1 nodes and leaves of 2 colors.at n=7A032103
- Let F(n) = Q(n) - P(n) be the Fortunate numbers (A005235); sequence gives n such that F(n) = prime(n+1).at n=12A035346
- Composite numbers whose prime factors contain no digits other than 3 and 7.at n=29A036316
- Positive numbers having the same set of digits in base 5 and base 6.at n=46A037429
- Numerators of continued fraction convergents to sqrt(607).at n=5A042164
- Base 8 palindromes that start with 3.at n=16A043023
- Numbers k such that 1 and 7 occur juxtaposed in the base-10 representation of k but not of k-1.at n=38A043230
- Numbers k such that 1 and 7 occur juxtaposed in the base-10 representation of k but not of k+1.at n=38A044010
- Numbers k such that string 1,4 occurs in the base 7 representation of k but not of k-1.at n=46A044149