8626
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 22
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 13680
- Proper Divisor Sum (Aliquot Sum)
- 5054
- 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
- 4068
- Möbius Function
- -1
- Radical
- 8626
- 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
- yes
- 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
- 52
- 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
- Number of asymmetric planar trees with n nodes.at n=13A005354
- a(0) = 1, a(n) = 11*n^2 + 2 for n>0.at n=28A010003
- Even pentagonal numbers.at n=38A014633
- Numbers k such that the continued fraction for sqrt(k) has period 74.at n=23A020413
- Convolution of natural numbers with (1, p(1), p(2), ... ), where p(k) is the k-th prime.at n=25A023538
- a(n) = least m such that if r and s in {1/1, 1/4, 1/7, ..., 1/(3n-2)} satisfy r < s, then r < k/m < (k+1)/m < s for some integer k.at n=41A024836
- a(n) = least m such that if r and s in {1/1, 1/3, 1/5, ..., 1/(2n-1)} satisfy r < s, then r < k/m < (k+2)/m < s for some integer k.at n=40A024841
- Dimension of invariant subspace of Lie polynomials of degree 2n under action of SL_2(C) on free Lie algebra of rank 2.at n=11A028351
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 92.at n=15A031590
- Pentagonal numbers with even index.at n=38A049452
- Number of prime-sextuplets up to 10^n.at n=10A063501
- Number of partitions of n with zero crank.at n=49A064410
- Numbers k such that k+1, k^2+1 and k^4+1 are primes.at n=29A070325
- Let X be the poset of finite subsets of the positive integers. The sequence is the number of downsets in X of cardinality n modulo equivalence by permutations of the positive integers.at n=19A087729
- Number of partitions of n in which every part occurs 1, 4, or 5 times. Also number of partitions of n in which every part is congruent to {1, 3, 4, 5, 7} mod 8.at n=47A100853
- Positive integers n such that n^14 + 1 is semiprime (A001358).at n=35A104335
- Pentagonal numbers for which the sum of the digits is also a pentagonal number.at n=10A117709
- Pentagonal numbers with only even digits.at n=5A117990
- a(n) is the first pentagonal number that is nontrivially the sum of two pentagonal numbers of the type P(p) + P(p+n) (we always have P(k) = P(0) + P(k)).at n=31A133312
- Pentagonal numbers that are the sum of a nonzero pentagonal number and a nonzero square in at least one way.at n=27A134938