6543
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 9464
- Proper Divisor Sum (Aliquot Sum)
- 2921
- 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
- 4356
- Möbius Function
- 0
- Radical
- 2181
- Omega Function (Ω)
- 3
- 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
- 137
- 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 7/6.at n=24A024643
- Number of partitions of n into parts not of the form 15k, 15k+4 or 15k-4. Also number of partitions with at most 3 parts of size 1 and differences between parts at distance 6 are greater than 1.at n=34A035958
- Number of partitions satisfying (cn(0,5) = cn(1,5) = cn(4,5) and cn(0,5) <= cn(2,5) and cn(0,5) <= cn(3,5)).at n=57A036824
- Number of partitions of n such that cn(0,5) = cn(1,5) <= cn(2,5) = cn(4,5) < cn(3,5).at n=68A036863
- Values of A038005 ending in 3.at n=4A038013
- a(n) is the least number k such that prime(k) - 1 is divisible by 2^(n-1) and the quotient is odd.at n=16A057776
- Numbers k for which phi(prime(k)) is a square.at n=42A062325
- (Sum of digits of n)^4 - (sum of digits of n^4).at n=27A069978
- (Sum of digits of n)^4 - (sum of digits of n^4).at n=9A069978
- (Sum of digits of n)^4 - (sum of digits of n^4).at n=45A069978
- Square root of n has the same nonzero digit in each of the first 4 places to the right of the decimal point.at n=1A073585
- Smallest available integer which fits into the repeating pattern 9876543210.at n=41A098756
- Chebyshev transform of the second kind of the Pell numbers.at n=15A112575
- Numbers k such that the decimal digits of phi(k) are a permutation of those of k.at n=14A115921
- Numbers that appear exactly five times in A101402. (Also indices of fives in A101403.).at n=4A129117
- Nonnegative numbers with digits in descending order that differ exactly by 1.at n=30A138142
- Where records occur in A001917.at n=14A152597
- a(n) + a(n+1) + a(n+2) = n^3.at n=28A152728
- a(n) = 81*n^2 - 2*n.at n=8A157507
- Start with 0; then add one to each single digit.at n=33A158699