2742
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
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 5496
- Proper Divisor Sum (Aliquot Sum)
- 2754
- 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
- 912
- Möbius Function
- -1
- Radical
- 2742
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 115
- 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
- Number of ordered rooted trees with n edges having root of odd degree.at n=8A000958
- Number of unrooted triangulations with reflection symmetry of a quadrilateral with n internal nodes.at n=8A005505
- Number of set-like molecular species of degree n.at n=17A007649
- a(n) = floor(n*(n-1)*(n-2)/17).at n=37A011899
- a(n) = floor( n*(n-1)*(n-2)/27 ).at n=43A011909
- [ 3rd elementary symmetric function of {sqrt(k+1)} ], k = 1,2,...,n.at n=8A025220
- Positions of record values in A030747.at n=47A030752
- Triangle of coefficients of generating function of 4-ary rooted trees of height at most n.at n=48A036606
- Number of 4-ary rooted trees with n nodes and height at most 4.at n=17A036609
- Numbers k such that the string 7,6 occurs in the base 9 representation of k but not of k-1.at n=36A044320
- Numbers n such that string 4,2 occurs in the base 10 representation of n but not of n-1.at n=30A044374
- Numbers n such that string 7,6 occurs in the base 9 representation of n but not of n+1.at n=36A044701
- Numbers n such that string 4,2 occurs in the base 10 representation of n but not of n+1.at n=30A044755
- Numbers whose base-4 representation contains exactly four 2's and one 3.at n=33A045154
- Numbers m such that the Bernoulli number B_m has denominator 42.at n=39A051228
- Consider all integer triples (i,j,k), j,k>0, with binomial(i+2, 3) = binomial(j+2, 3) + k^3, ordered by increasing i; sequence gives j values.at n=20A054222
- Number of self-conjugate three-quadrant Ferrers graphs that partition n.at n=40A059777
- a(1) = 1; thereafter a(n+1) = a(n) + product of nonzero digits of a(n).at n=45A063108
- Dimension of the space of weight n cuspidal newforms for Gamma_1( 69 ).at n=21A063342
- Least k such that k*7^n +/- 1 are twin primes.at n=28A064217