9875
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 29
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 12480
- Proper Divisor Sum (Aliquot Sum)
- 2605
- 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
- 7800
- Möbius Function
- 0
- Radical
- 395
- Omega Function (Ω)
- 4
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 135
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- 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
- n written in fractional base 10/9.at n=35A024664
- Numbers whose set of base-8 digits is {2,3}.at n=39A032808
- Numbers k such that phi(k)*d(k) is a multiple of sigma(k), where d(k) is the number of divisors of k.at n=36A050934
- Numbers n such that n | 10^n + 9^n + 1.at n=28A057295
- Total number of parts which are positive powers of 2 in all partitions of n.at n=27A073119
- Column 2 of triangle A091602.at n=43A091605
- String of digits encountered in decimal expansion of successive ratios k/(k+1), treating only non-repeating expansions, with decimal point and leading and trailing zeros removed.at n=12A156703
- Twin natural nonprimes with nonprime number of prime factors.at n=39A171995
- Monotonic ordering of nonnegative differences 10^i-5^j, for 40>= i>=0, j>=0.at n=13A192202
- Number of 4-bead necklaces labeled with numbers -n..n not allowing reversal, with sum zero and avoiding the patterns z z+1 z+2 and z z-1 z-2.at n=18A209116
- Numbers n such that n!3 - 3^5 is prime.at n=29A247465
- The growth series for the affine Weyl group E_8.at n=8A267176
- The Pnictogen sequence: a(n) = A018227(n)-3.at n=35A271995
- Expansion of 1/(1 - Sum_{k>=1} x^prime(prime(k))).at n=51A281422
- Numbers k such that A090086(k), the smallest pseudoprime to base k (not necessarily exceeding k), is a Carmichael number.at n=14A293203
- Where records occur in A171898.at n=36A309814
- Number of unlabeled rooted trees with n nodes in which the branches of any node with more than one distinct branch have empty intersection.at n=12A316501
- Numbers k such that k^2 and k^3, when reversed, are prime.at n=43A320909
- Number of times the digit 7 appears in the first 10^n decimal digits of Euler's number e = exp(1), counting starts after the decimal point.at n=4A322722
- The binary expansion of a(n) is the first n terms of 2 - A000002.at n=14A329356