7085
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 9240
- Proper Divisor Sum (Aliquot Sum)
- 2155
- 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
- 5184
- Möbius Function
- -1
- Radical
- 7085
- Omega Function (Ω)
- 3
- 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
- 57
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- 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
- a(n) = a(n-2) + a(n-5).at n=48A001687
- 4-dimensional analog of centered polygonal numbers.at n=11A006323
- Numbers k such that the continued fraction for sqrt(k) has period 15.at n=33A020354
- a(n) = n*(21*n-1)/2.at n=26A022278
- Numbers that are the sum of 2 nonzero squares in exactly 4 ways.at n=38A025287
- Numbers that are the sum of 2 nonzero squares in 4 or more ways.at n=39A025295
- Numbers that are the sum of 2 distinct nonzero squares in exactly 4 ways.at n=38A025305
- Numbers that are the sum of 2 distinct nonzero squares in 4 or more ways.at n=39A025314
- a(n) = T(2n,n-1), T given by A026670. Also T(2n,n-1)=T(2n+1,n+2), T given by A026725; and T(2n,n-1), T given by A026736.at n=6A026672
- a(n) = greatest number in row n of array T given by A026736.at n=14A027214
- Coefficients in expansion of Sum_{k>=0} Product_{j=1..k} (1-x^j) about x = -1.at n=4A035378
- Number of partitions of n into parts 3k and 3k+2 with at least one part of each type.at n=53A035619
- Numerators of continued fraction convergents to sqrt(190).at n=10A041352
- Numerators of continued fraction convergents to sqrt(760).at n=6A042464
- a(n) = binomial(n,0) - binomial(n,2) + binomial(n,4).at n=22A058923
- Sum of n-th row of triangle of primes: 2; 2 3 2; 2 3 5 3 2; 2 3 5 7 5 3 2; ...; where n-th row contains 2n+1 terms.at n=42A061802
- Binary string self-substitutions: a(n) is obtained by substituting the binary expansion of n for each 1-bit in the binary expansion of n.at n=13A065159
- Let p and q be two prime numbers, not necessarily consecutive, such that q - p = 2n; then a(n) is the number of partitions of 2n into even numbers so that each partition corresponds to a consecutive prime difference pattern (k-tuple) and p <= A000230(n).at n=47A079023
- Numbers m that are the hypotenuse of exactly 13 distinct integer-sided right triangles, i.e., m^2 can be written as a sum of two squares in 13 ways.at n=31A097102
- a(n) is the least k such that (10^k)*Mersenne-prime(n) + 1 is prime.at n=26A102629