7842
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 15696
- Proper Divisor Sum (Aliquot Sum)
- 7854
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- yes
Derived Values
- Euler's Totient
- 2612
- Möbius Function
- -1
- Radical
- 7842
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 52
- 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
- yes
- Odd
- no
Appears in sequences
- Numbers k such that 2*3^k + 1 is prime.at n=26A003306
- Numbers that are the sum of 7 nonzero 8th powers.at n=13A003385
- Number of points on surface of cuboctahedron (or icosahedron): a(0) = 1; for n > 0, a(n) = 10n^2 + 2. Also coordination sequence for f.c.c. or A_3 or D_3 lattice.at n=28A005901
- a(0) = 1, a(n) = 40*n^2 + 2 for n>0.at n=14A010022
- 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 88.at n=6A031586
- Nearest integer to log(n)^sqrt(n).at n=44A062464
- Number of two-rowed partitions of length 6.at n=22A070559
- Let r, s, t be three permutations of the set { 1, 2, 3, ..., n }; a(n) = minimal value of Sum_{i=1..n} r(i)*s(i)*t(i).at n=17A070735
- a(1) = 1, a(n+1) is the smallest number such that there are n primes between a(n) and a(n+1) exclusive.at n=44A075342
- Concerning the popular MMORPG "Runescape" by JAGeX corporation, this sequence gives the number of experience points needed for a given level in a skill.at n=24A111078
- <h[d+1,d-1],s[d,d]*s[d,d]*s[d,d]> where h[d+1,d-1] is a homogeneous symmetric function, s[d,d] is a Schur function indexed by two parts, * represents the Kronecker product and <, > is the standard scalar product on symmetric functions.at n=28A115376
- Number of different values of i^2+j^2+k^2+l^2+m^2+n^2 for i,j,k,l,m,n in [0,n].at n=38A132438
- Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0) and consisting of n steps taken from {(-1, -1), (-1, 1), (1, 0)}.at n=12A151255
- Number of paths from (0,0) to (n+2,n) using only up and right steps and avoiding two or more consecutive moves up or three or more consecutive moves right.at n=35A177787
- Denominators of Bernoulli numbers which are congruent to 3 (mod 9).at n=40A219543
- Bernoulli denominators with 8 divisors in increasing order (without repetitions).at n=35A219742
- a(n) is the minimal k such that nextprime(2k+1) - 2k = prime(n) where nextprime(n) is least prime > n.at n=13A229512
- Start of a triple of consecutive squarefree numbers each of which has exactly 3 distinct prime factors.at n=48A242606
- Number of compositions of n if all summand runs are kept together.at n=19A274174
- Sum of the largest parts in the partitions of n into 5 squarefree parts.at n=46A308845