1879
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 25
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 1880
- Proper Divisor Sum (Aliquot Sum)
- 1
- 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
- 1878
- Möbius Function
- -1
- Radical
- 1879
- Omega Function (Ω)
- 1
- Little Omega Function (ω)
- 1
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
- 86
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- yes
- Composite Number
- no
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- yes
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 289
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Primes p of the form 3k+1 such that sum_{x=1..p} cos(2*Pi*x^3/p) < -sqrt(p).at n=27A000923
- Primes with 6 as smallest primitive root.at n=19A001125
- Let i, i+d, i+2d, ..., i+(n-1)d be an n-term arithmetic progression of primes; choose the one which minimizes the last term; then a(n) = last term i+(n-1)d.at n=8A005115
- a(n) is the number of integers m which take n steps to reach 1 in '3x+1' problem.at n=34A005186
- Greatest k such that binomial(k,n) has fewer than n distinct prime factors.at n=19A005735
- Primes of form 2n^2 - 2n + 19.at n=25A007639
- a(n) = prime(n^2).at n=16A011757
- Odd primes such that (3p+1)/2 and 3p+4 are also prime.at n=20A014223
- Six iterations of Reverse and Add are needed to reach a palindrome.at n=33A015984
- Primes that are palindromic in base 2 (but written here in base 10).at n=17A016041
- Numbers k such that the continued fraction for sqrt(k) has period 68.at n=0A020407
- Place where n-th 1 occurs in A023119.at n=37A022781
- a(n) = M(n) + m(n) for n >= 2, where M(n) = max{ a(i) + a(n-i): i = 1..n-1 }, m(n) = min{ a(i) + a(n-i): i = 1..n-1 }.at n=17A022905
- Primes p such that 3*p + 4 and 9*p + 16 are also prime.at n=28A023247
- Primes that remain prime through 2 iterations of function f(x) = 7x + 6.at n=25A023259
- Discriminants of quartic fields with 2 complex conjugates (negated).at n=42A023681
- Smallest prime in Goldbach partition of A025018(n).at n=36A025019
- a(n) = (1/1 - 1/2 + ... + (-1)^(n-1)/n)*lcm{1..n}.at n=8A025530
- Triangle read by rows: square of the lower triangular mean matrix.at n=40A027446
- Primes with even number of 1's in binary expansion such that next prime also has even number of 1's.at n=45A027701