1679
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 23
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 5
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 1776
- Proper Divisor Sum (Aliquot Sum)
- 97
- 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
- 1584
- Möbius Function
- 1
- Radical
- 1679
- 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
- yes
- Harshad Number
- yes
- Narcissistic Number
- no
- Collatz Steps
- 86
- 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
- G.f.: 1/Product_{k>=1} (1-prime(k)*x^prime(k)).at n=15A002098
- Smallest multiple of n whose digits sum to n.at n=23A002998
- a(1) = 1; for n>1, a(n) = a(n-1) + 1 + sum of distinct prime factors of a(n-1) that are < a(n-1).at n=50A003508
- Coordination sequence T1 for Zeolite Code AEL.at n=27A008004
- Coordination sequence T2 for Zeolite Code AEL.at n=27A008005
- a(n) = n^2 - 2.at n=40A008865
- Number of parts in all partitions of n into distinct parts.at n=31A015723
- Numbers n such that n is a substring of its square in base 3 (written in base 10).at n=16A018827
- a(n) = (1/2)*(n-th largest even number in array T given by A027170).at n=46A027184
- 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 39.at n=16A031537
- Least D in the Pellian x^2 - D*y^2 = 1 for which y has least solution n.at n=40A033318
- Coordination sequence T2 for Zeolite Code SBE.at n=33A033605
- Multiplicity of highest weight (or singular) vectors associated with character chi_47 of Monster module.at n=48A034435
- Number of partitions of n into parts not of the form 19k, 19k+4 or 19k-4. Also number of partitions with at most 3 parts of size 1 and differences between parts at distance 8 are greater than 1.at n=26A035973
- a(n) = prime(n)*prime(n+1) - prime(n) - prime(n+1).at n=12A037165
- Denominators of continued fraction convergents to sqrt(719).at n=10A042385
- Numerators of continued fraction convergents to sqrt(838).at n=3A042618
- Numbers k such that 5 and 6 occur juxtaposed in the base-9 representation of k but not of k-1.at n=41A043210
- Numbers k such that 7 and 9 occur juxtaposed in the base-10 representation of k but not of k-1.at n=32A043259
- Numbers k such that 5 and 6 occur juxtaposed in the base-9 representation of k but not of k+1.at n=41A043990