7979
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 32
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 8160
- Proper Divisor Sum (Aliquot Sum)
- 181
- 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
- 7800
- Möbius Function
- 1
- Radical
- 7979
- 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
- 52
- 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
- Numerators of continued fraction convergents to sqrt(53).at n=6A041090
- Numerators of continued fraction convergents to sqrt(212).at n=10A041394
- Numerators of continued fraction convergents to sqrt(848).at n=4A042636
- n-th 4k+1 prime times n-th 4k-1 prime.at n=11A048630
- Sum of digits = 8 times number of digits.at n=21A061425
- Odd composite numbers which in base 2 contain their largest proper factor as a substring of digits.at n=19A063131
- Composite numbers not divisible by 2, 3, 5 or 7 which in base 2 contain their largest proper factor as a substring.at n=15A063138
- Least composite number not congruent to 0 (modulo the first n primes) which contains its greatest proper divisor as a substring of itself, both in base two.at n=20A077658
- Least composite number not congruent to 0 (modulo the first n primes) which contains its greatest proper divisor as a substring of itself, both in base two.at n=21A077658
- a(n) = round(n^3/12) - floor(n/4)*floor((n+2)/4).at n=46A090676
- Numbers n such that the partition function A000041(k) is even and odd the same number of times for 0 <= k <= n.at n=12A098936
- Planar trees where no branch is identical to its adjacent neighbor.at n=14A106363
- Bases of the n-th powers in A090900.at n=24A110042
- a(n) = n^3 - n - 1.at n=19A126420
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (-1, 1, -1), (-1, 1, 0), (0, 0, 1), (1, 0, 0)}.at n=8A149925
- Engel expansion of hz = limit_{k -> infinity} 1 + k - Sum_{j = -k..k} exp(-2^j).at n=17A159835
- Coefficients in the expansion of C/B^2, in Watson's notation of page 118.at n=17A160525
- a(n) = 3*A022004(n) + 8.at n=27A163635
- Double primes: concatenation of the n-th prime with itself.at n=21A176597
- Numbers n such that phi(n) = phi(n+12) and n is not divisible by 2.at n=21A217141