12369
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 20480
- Proper Divisor Sum (Aliquot Sum)
- 8111
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6480
- Möbius Function
- 1
- Radical
- 12369
- Omega Function (Ω)
- 4
- Little Omega Function (ω)
- 4
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
- 63
- 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
- Geometric mean of phi(n) and sigma(n) is an integer, n odd.at n=30A015705
- Number of partitions of n with equal nonzero number of parts congruent to each of 1 and 3 (mod 4).at n=44A035550
- A035550 with periodic zeros stripped.at n=21A035595
- Numbers having four 3's in base 6.at n=32A043384
- Numbers whose base-5 representation contains exactly three 3's and three 4's.at n=5A045307
- Staircase of coefficients of polynomials used for column g.f.s of triangle A060923.at n=42A061186
- Intersection of A065764 and A065765: n such that x and y exist with sigma[x^2] = n = sigma[2*(y^2)].at n=2A065767
- a(n) is the smallest number m such that for the n-digit number s=10^(n-1)+ m, 10*s+1, 10*s+3, 10*s+7 and 10*s+9 are primes.at n=11A097639
- Expansion of 1/((1-x)^2*(1-x^2)^2*(1-x^3)).at n=39A097701
- Lesser of a,b where n^2 = a^3 + b^3; a,b > 0 and gcd(a,b)=1. The greater of a,b is the corresponding term in A099533 and n, which is used to order this sequence, is the corresponding term in A099426.at n=35A099532
- Numbers n such that (n / sum of digits of n) is a golden semiprime.at n=10A108780
- Alkane systems (see Cyvin reference for precise definition).at n=10A121184
- Numbers k such that binomial(4k, k) - 1 is prime.at n=15A125240
- a(n) = 104*n + 9977.at n=23A126978
- a(n) is the concatenation in increasing order of all single-digit divisors of n.at n=17A129476
- a(n) is the concatenation in increasing order of all single-digit divisors of n.at n=53A129476
- Numbers k that divide the sum of digits of 21^k.at n=58A175589
- Numbers having exactly four representations by the quadratic form x^2+xy+y^2 with 0<=x<=y.at n=34A198775
- Numbers k such that sigma(k - 2) = sigma(k + 2).at n=16A223091
- Proceed counterclockwise on the outer keys of a numeric keypad (i.e., 1,2,3,6,9,8,7,4): first single digits, then concatenate two digits, then three, etc.at n=32A249182