7081
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 16
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 7252
- Proper Divisor Sum (Aliquot Sum)
- 171
- 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
- 6912
- Möbius Function
- 1
- Radical
- 7081
- 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
- 101
- 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 that are the sum of 11 positive 8th powers.at n=14A003389
- Pseudoprimes to base 9.at n=43A020138
- Pseudoprimes to base 22.at n=35A020150
- Pseudoprimes to base 24.at n=27A020152
- Strong pseudoprimes to base 43.at n=10A020269
- Numbers k such that the continued fraction for sqrt(k) has period 78.at n=16A020417
- a(n) = least m such that if r and s in {1/1, 1/3, 1/5, ..., 1/(2n-1)} satisfy r < s, then r < k/m < (k+3)/m < s for some integer k.at n=31A024844
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 44 ones.at n=22A031812
- a(n) = (3*n+1)*(4*n+1).at n=24A033577
- Number of partitions of n into parts not of the form 17k, 17k+4 or 17k-4. Also number of partitions with at most 3 parts of size 1 and differences between parts at distance 7 are greater than 1.at n=34A035965
- a(n)=(s(n)+3)/10, where s(n)=n-th base 10 palindrome that starts with 7.at n=30A043086
- Lexicographically earliest increasing sequence of positive integers such that A001222(a(i)+a(j)) = A001222(a(i)) + A001222(a(j)) for all 1<=i<j.at n=5A059363
- a(n) = (2*n-1)^2 + (2*n)^2.at n=29A060820
- Composite and every divisor (except 1) contains the digit 7.at n=35A062676
- Numbers having exactly twelve anti-divisors.at n=29A066478
- a(n) = 8*n^2 - 4*n + 1.at n=30A080856
- Third row of Pascal-(1,5,1) array A081580.at n=20A081589
- If mod[n,4]=0 then a(n)=a(n-1), if mod[n,4]=1 then a(n)=a(n-2)+a(n-3), if mod[n,4]=2 then a(n)=a(n-3)+a(n-4)+a(n-5), if mod[n,4]=2 then a(n)=a(n-4)+a(n-5)+a(n-6)+a[n-7].at n=33A104205
- Sums of p-th to the q-th prime where p and q are consecutive primes.at n=38A114381
- Products of two primes that are not Chen primes.at n=16A115719