9979
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 34
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 10584
- Proper Divisor Sum (Aliquot Sum)
- 605
- 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
- 9376
- Möbius Function
- 1
- Radical
- 9979
- Omega Function (Ω)
- 2
- Little Omega Function (ω)
- 2
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
- no
- Narcissistic Number
- no
- Collatz Steps
- 73
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
- Numerators of continued fraction convergents to sqrt(14).at n=10A041020
- Numerators of continued fraction convergents to sqrt(126).at n=4A041228
- Numerators of continued fraction convergents to sqrt(686).at n=6A042318
- Denominators of continued fraction convergents to sqrt(884).at n=10A042709
- Numbers having three 9's in base 10.at n=25A043527
- Numbers whose base-5 representation contains exactly two 0's and three 4's.at n=28A045213
- a(n) is the smallest nonprime k such that tau(k + n) = tau(k) + n , where tau(n) is the number of divisors of n (A000005).at n=20A099642
- Near-repdigit semiprimes with 9 as repeated digit.at n=22A105990
- Composite numbers between largest n-digit prime and the smallest (n+1) digit prime.at n=22A109936
- Numbers with rounded up arithmetic mean of digits = 9.at n=41A178369
- Number of (n+1)X(2+1) 0..2 arrays with the sum of each 2X2 subblock maximum and minimum lexicographically nondecreasing rowwise and columnwise.at n=1A236078
- T(n,k)=Number of (n+1)X(k+1) 0..2 arrays with the sum of each 2X2 subblock maximum and minimum lexicographically nondecreasing rowwise and columnwise.at n=4A236082
- Indices of the start of 9 successive distinct digits in the decimal expansion of e (2.718281828...).at n=35A258167
- Molien series for invariants of finite Coxeter group D_12 (bisected).at n=33A266775
- Numbers n such that the Collatz iterations for n and n + 1 have the same length (A078417) but do not meet a certain condition. (See comments.)at n=9A274410
- Erroneous version of A274410.at n=5A274411
- Numbers with digits 7 and 9 only.at n=27A285011
- Number of perfect disconnected simple graphs on n nodes.at n=8A286949
- Numbers in which 9 outnumbers all other digits together.at n=53A292739
- Number of n X n 0..1 arrays with every element equal to 0, 1, 2, 4 or 7 king-move adjacent elements, with upper left element zero.at n=10A298488