8990
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 26
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 17280
- Proper Divisor Sum (Aliquot Sum)
- 8290
- 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
- 3360
- Möbius Function
- 1
- Radical
- 8990
- 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
- 78
- 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
- a(n) = 2*binomial(n,3).at n=31A007290
- a(n) = floor(binomial(n,4)/4).at n=32A011850
- Numbers in which 0,1,2,3,4,5 all occur in base 6.at n=21A031947
- Digitally balanced numbers in base 6: equal numbers of 0's, 1's, ..., 5's.at n=21A049357
- Number of digraphs on n unlabeled nodes with a sink (or, with a source).at n=4A051421
- Denominator of b(n)-b(n+1), where b(n) = n/((n+1)(n+2)) = A026741/A045896.at n=27A051713
- Integers n > 1997 such that the 'Reverse and Add!' trajectory of n joins the trajectory of 1997.at n=16A063055
- Partition the concatenation 1234567...of natural numbers into successive strings which are even, all different and > 2. (0 never taken as the most significant digit.)at n=57A077295
- Number of partitions of n such that the least part occurs exactly three times.at n=43A097091
- Nontrivial slowest increasing sequence whose succession of digits is that of the nonnegative integers.at n=45A098080
- Minimal numbers m such that number of positive integers whose harmonic mean with m is n.at n=54A114585
- n times n+2 gives the concatenation of two numbers m and m-3.at n=2A116266
- a(n) = Sum_{k=1..phi(n)-1} t(n,k)*t(n,k+1), where t(n,k) is the k-th positive integer which is coprime to n and phi(n) is the number of positive integers which are <= n and are coprime to n.at n=30A119584
- Number of base 30 n-digit numbers with adjacent digits differing by three or less.at n=4A126498
- Numbers k such that k and k^2 use only the digits 0, 1, 2, 8 and 9.at n=31A136835
- Row sums from A144562.at n=19A144640
- Twice 13-gonal numbers: a(n) = n*(11*n - 9).at n=29A152997
- a(n) = 250*n - 10.at n=35A154378
- The initial decimal digits of 2^a(n) are the decimal digits of n followed by n.at n=17A171652
- Denominators of rationals with e.g.f. D(3,x), a Debye function.at n=28A227571