9817
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 25
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 9818
- Proper Divisor Sum (Aliquot Sum)
- 1
- 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
- 9816
- Möbius Function
- -1
- Radical
- 9817
- Omega Function (Ω)
- 1
- Little Omega Function (ω)
- 1
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
- 135
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- yes
- Composite Number
- no
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 1211
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- a(n) = floor(n*(n-1)*(n-2)/4).at n=35A011886
- Numbers k such that the continued fraction for sqrt(k) has period 95.at n=5A020434
- Number of ways to partition n elements into pie slices of different sizes of at least 2 allowing the pie to be turned over.at n=40A032230
- Primes which are not the sum of consecutive composite numbers.at n=33A037174
- Numbers whose base-4 representation contains exactly four 1's and three 2's.at n=27A045108
- Primes base 10 that remain primes in five bases b, 2<=b<=10, expansions interpreted as decimal numbers.at n=32A052029
- Primes which are the concatenation of numbers n_1, n_2, n_3, in that order, with n_1 + n_2 = n_3 (leading zeros are forbidden for nonzero n_i).at n=10A067860
- Odd prime values of sigma(k) - phi(k) taking k in increasing order.at n=35A068419
- Numbers n such that 2*p(n)+3, 2*p(n+1)+3, 2*p(n+2)+3 are consecutive primes, where p(i) denotes the i-th prime.at n=13A088066
- Primes in which the digit string can be partitioned into three parts such that the sum of the first two is equal to the third, and the second part is nonzero.at n=9A088291
- Numbers n such that n, n+1 and n+2 are 1,2,3-almost primes.at n=36A112998
- Numbers k such that k, k+1, k+2 and k+3 are 1,2,3,4-almost primes.at n=11A113000
- Number of doubletons in all partitions of n. By a doubleton in a partition we mean an occurrence of a part exactly twice (the partition [4,(3,3),2,2,2,(1,1)] has two doubletons, shown between parentheses).at n=34A116646
- Start with 1 and repeatedly reverse the digits and add 42 to get the next term.at n=19A118075
- Primes of the form 12*x^2+12*x*y+73*y^2.at n=35A139990
- 1 together with terms of A037174.at n=34A140464
- Primes of the form 28x^2+12xy+57y^2.at n=34A140621
- Primes of the form 33x^2+24xy+88y^2.at n=40A140627
- Primes congruent to 15 mod 29.at n=38A141991
- Primes congruent to 21 mod 31.at n=38A142025