7071
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 9432
- Proper Divisor Sum (Aliquot Sum)
- 2361
- 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
- 4712
- Möbius Function
- 1
- Radical
- 7071
- 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
- 57
- 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
- Pair up the numbers.at n=35A030656
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 27.at n=38A031525
- a(n) = floor(10000/sqrt(n)).at n=1A033433
- a(n)=(s(n)+3)/10, where s(n)=n-th base 10 palindrome that starts with 7.at n=29A043086
- a(n) = T(n,n-3), array T as in A055818.at n=31A055820
- Composites for which the row of the prime-composite array (A063173) includes the leftmost element of both a zero-only antidiagonal and a zero-only diagonal(A067681).at n=43A063176
- Partition the concatenation 1234567... of natural numbers into successive strings which are multiples of 3 all different and > 3. (0 never taken as the most significant digit.)at n=44A077296
- Sum of numbers in n-th upward diagonal of triangle in A079826.at n=35A079825
- Integer part of Lorentz gamma factor = 1/sqrt(1 - (beta)^2) for beta = 0.9999...(with 9 appearing n times) = 1 - 10^(-n).at n=7A109999
- Triangle read by rows, T(n, k) = Sum_{j=0..n} C(n-j, n-k)*E2(n, j), where E2 are the second-order Eulerian numbers A201637, for n >= 0 and 0 <= k <= n.at n=30A112493
- Third column of triangle A112493 used for e.g.f.s of Stirling2 diagonals.at n=5A112495
- Triangle read by rows: T(n,k) is the number of partitions of an n-set having k blocks of size > 1 (0<=k<=floor(n/2)).at n=27A124324
- Numbers k such that k and k^2 use only the digits 0, 1, 4, 7 and 9.at n=20A136865
- Number of permutations of 1..n containing the relative rank sequence { 41523 } at any spacing.at n=3A158426
- Sum of binary digits of all primes < 2^n, i.e., with at most n binary digits.at n=12A168155
- Where A184593, the difference between 5n and A101306(n), becomes a new record in either direction.at n=45A184594
- Number of arrays of n integers in -7..7 with sum zero and equal numbers of elements greater than zero and less than zero.at n=4A201810
- Number of arrays of 5 integers in -n..n with sum zero and equal numbers of elements greater than zero and less than zero.at n=6A201813
- Coefficients of the nonnegative powers of rho(11) = 2*cos(Pi/11) when written in the power basis of the degree 5 number field Q(rho(11)). Coefficients of the third power.at n=14A231185
- Number of palindromic partitions of n whose greatest part has multiplicity <= 4.at n=48A238787