12990
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
- 1
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 31248
- Proper Divisor Sum (Aliquot Sum)
- 18258
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 3456
- Möbius Function
- 1
- Radical
- 12990
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 50
- 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
- Expansion of Product_{m>=1} 1/(1 + m*q^m)^5.at n=14A022697
- Integers expressible as the sum of (at least two) consecutive primes in at least 4 ways.at n=28A067374
- Number of base 10 n-digit numbers with adjacent digits differing by three or less.at n=5A126478
- a(n) = 36*n^2 - 6.at n=18A158462
- Number of nX1 binary arrays with the number of 0-1 adjacencies equal to the number of 0-0 adjacencies.at n=17A183256
- a(n) = n*(14*n + 13).at n=30A195028
- Numbers that are the sum of 10 consecutive primes and also the sum of 10 consecutive semiprimes.at n=2A284102
- Numbers k such that Bernoulli number B_{k} has denominator 14322.at n=15A295588
- Numbers k such that A003132(k^2) = A003132(k), where A003132(n) is the sum of the squares of the digits of n.at n=51A309883
- Number of ways to split a strict integer partition of n into consecutive subsequences of equal length.at n=52A323434
- a(n) is the smallest number that can be partitioned into n ways as the sum of two Moran numbers.at n=29A337862
- a(n) = n * (binomial(n,2) - 2).at n=30A341768
- Squarefree composite numbers m such that k - m^2 < m, where k is the smallest number greater than m^2 such that rad(k) | m.at n=22A362003
- E.g.f. A(x) satisfies A(x) = 1 + x^2*exp(x)*A(x)^3.at n=6A390647