13221
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 9
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 20748
- Proper Divisor Sum (Aliquot Sum)
- 7527
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 8064
- Möbius Function
- 0
- Radical
- 4407
- 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
- yes
- Harshad Number
- yes
- Narcissistic Number
- no
- Collatz Steps
- 50
- 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
- a(n) = (4*n+1)*(4*n+5).at n=28A003185
- Nearest integer to Gamma(n + 7/11)/Gamma(7/11).at n=8A020008
- Ceiling of Gamma(n+7/11)/Gamma(7/11).at n=8A020098
- Base 9 digits are, in order, the first n terms of the periodic sequence with initial period 2,0,1.at n=4A037518
- Let R(i,j) be the rectangle with antidiagonals 1; 2,3; 4,5,6; ...; the n-th Lucas number is in antidiagonal a(n).at n=38A057045
- Numbers k such that the smoothly undulating palindromic number (38*10^k - 83)/99 is a prime.at n=8A062220
- Ado [Simone Caramel]'s function: a(0) = 1, a(n) = a(n-1) + 2*(Fibonacci(n+1)-n), n > 0.at n=17A064551
- Factorial expansion of A071156.at n=33A071158
- Numbers n of the form k + reverse(k) for exactly three k.at n=31A071914
- Adjacent generalized Fermat primes.at n=7A118539
- Third trisection of A061037.at n=37A142600
- a(n) = 100*n^2 + 100*n + 21.at n=11A152161
- Number of correlation classes for pairs of different words in an alphabet of size 4.at n=11A152959
- a(1)=2, a(2)=2, a(n)=a(n-2)+floor(a(n-2)*a(n-1)/(a(n-2)+a(n-1))).at n=42A173091
- Trisection A061037(3*n-2) of the Balmer spectrum numerators extended to negative indices.at n=39A174325
- Number of semistandard Young tableaux over all partitions of 5 with maximal element <= n.at n=9A210427
- a(n) = numerator of the fraction whose Engel expansion has the positive divisors of n as its terms.at n=19A220847
- Number of (n+2) X (4+2) 0..1 arrays with no 3 x 3 subblock diagonal sum less than the antidiagonal sum or central row sum less than the central column sum.at n=5A258890
- Number of (n+2) X (6+2) 0..1 arrays with no 3 x 3 subblock diagonal sum less than the antidiagonal sum or central row sum less than the central column sum.at n=3A258892
- Number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 3", based on the 5-celled von Neumann neighborhood.at n=57A269910