8420
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 14
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 17724
- Proper Divisor Sum (Aliquot Sum)
- 9304
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 3360
- Möbius Function
- 0
- Radical
- 4210
- Omega Function (Ω)
- 4
- 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
- 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
- 127
- 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
- yes
- Odd
- no
Appears in sequences
- Number of symmetric foldings of a strip of n blank stamps.at n=19A001010
- Apply partial sum operator twice to binary rooted tree numbers.at n=14A014168
- Cycle class sequence c(n) (the number of true cycles of length n in which a certain node is included) for zeolite MFI = ZSM-5 Nan[AlnSi96-nO192] starting with a T5 atom.at n=12A019162
- a(n) = difference between greatest two Stirling numbers S(n,k) of second kind, for k = 1,2,...,n.at n=7A024433
- a(n) = Sum_{k=0..2n-1} T(n,k) * T(n,k+1), with T given by A027052.at n=5A027079
- a(n) = n^3 + n^2 + n.at n=20A027444
- Arrange digits of 2^n in descending order.at n=11A028910
- Sum of distinct powers of 20; i.e., numbers with digits in {0,1} base 20; i.e., write n in base 2 and read as if written in base 20.at n=14A063012
- Numbers k such that phi(sigma(k)+k) = sigma(k-phi(k)), where phi is A000010 and sigma is A000203.at n=27A063710
- Nested floor product of n and fractions (k+1)/k for all k>0 (mod 3), divided by 3.at n=39A073360
- a(n) = -1/16-3*n^2/8+17*n/12+n^3/12+(-1)^n/16.at n=47A088795
- Bisection of A001157: a(n) = sigma_2(2n-1).at n=43A099978
- Least k such that 10^n + k - 1 is the first of a pair of twin primes.at n=34A103129
- Numbers with even decimal digits in decreasing order.at n=26A119261
- Diagonal above the central terms of pendular trinomial triangle A119369, ignoring leading zeros.at n=7A119375
- Row sums of triangle A120072 (numerator triangle for H atom spectrum).at n=23A120074
- Triangle T, read by rows, where column k equals column k of T^(2^k) shift down 1 row, with T(n,n)=T(n+1,n)=1 for n>=0.at n=37A121395
- Column 1 of triangle T=A121395, where column k of T equals column k of T^(2^k) shift down 1 row.at n=7A121396
- Numbers k such that the sum of the first k primes is prime and the sum of the squares of the first k primes is also prime.at n=39A124225
- Numbers k such that k^2 divides 13^k - 1.at n=46A128393