7897
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 31
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 8100
- Proper Divisor Sum (Aliquot Sum)
- 203
- 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
- 7696
- Möbius Function
- 1
- Radical
- 7897
- 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
- 39
- 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
- Numbers k such that the continued fraction for sqrt(k) has period 23.at n=32A020362
- Numbers with exactly 7 1's in their ternary expansion.at n=28A023698
- Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted then there are a pair of central terms both equal to 5.at n=39A031418
- Number of partitions of n into parts not of form 4k+2, 24k, 24k+9 or 24k-9. Also number of partitions in which no odd part is repeated, with at most 4 parts of size less than or equal to 2 and where differences between parts at distance 5 are greater than 1 when the smallest part is odd and greater than 2 when the smallest part is even.at n=46A036033
- Denominators of continued fraction convergents to sqrt(895).at n=6A042731
- Numbers k such that 37*2^k-1 is prime.at n=3A050544
- Positions of powers of 2 in A064413 (if it starts at 2).at n=12A064468
- Centered heptagonal numbers.at n=47A069099
- Numbers n such that when the digits of Fibonacci(n) are sorted into decreasing order and zeros are dropped it is a prime.at n=47A082922
- a(n) = 49n^2 - 28n - 20.at n=12A118058
- Start with 1 and repeatedly reverse the digits and add 76 to get the next term.at n=48A118226
- a(n) = ceiling(Sum_{i=1..n-1} a(i)/4) for n >= 2 starting with a(1) = 1.at n=43A120160
- Number of correlation classes for pairs of different words in an alphabet of size 4.at n=10A152959
- a(n) = prime(n)^2 - n.at n=23A182174
- 7-distance Pell sequence.at n=41A237716
- Semiprimes which are the arithmetic mean of three consecutive primes.at n=31A242218
- Number of length n+2 0..4 arrays with no three unequal elements in a row and no three equal elements in a row and new values 0..4 introduced in 0..4 order.at n=10A243723
- Numbers k such that k, k+1, k+2, and k+3 are not divisible by any of their nonzero digits.at n=39A244358
- Number of (n+2)X(1+2) 0..3 arrays with every 3X3 subblock row and column sum nonprime and every diagonal and antidiagonal sum prime.at n=8A251838
- T(n,k)=Number of (n+2)X(k+2) 0..3 arrays with every 3X3 subblock row and column sum nonprime and every diagonal and antidiagonal sum prime.at n=36A251845