2047
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 2160
- Proper Divisor Sum (Aliquot Sum)
- 113
- 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
- 1936
- Möbius Function
- 1
- Radical
- 2047
- 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
- 156
- 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
- a(n) = 2^n - 1. (Sometimes called Mersenne numbers, although that name is usually reserved for A001348.)at n=11A000225
- Numbers k such that (1,k) is "good".at n=25A000696
- Number of combinatorial types of simplicial n-dimensional polytopes with n+3 nodes.at n=12A000943
- 10-gonal (or decagonal) numbers: a(n) = n*(4*n-3).at n=23A001107
- a(n) is the solution to the postage stamp problem with 5 denominations and n stamps.at n=11A001210
- Strong pseudoprimes to base 2.at n=0A001262
- Mersenne numbers: 2^p - 1, where p is prime.at n=4A001348
- Fermat pseudoprimes to base 2, also called Sarrus numbers or Poulet numbers.at n=7A001567
- Numbers k such that phi(2k+1) < phi(2k).at n=25A001837
- Centered octahedral numbers (crystal ball sequence for cubic lattice).at n=11A001845
- Numerators of the Taylor coefficients of (e^x-1)^2.at n=10A002678
- Woodall (or Riesel) numbers: n*2^n - 1.at n=7A003261
- Divisors of 2^22 - 1.at n=7A003531
- Divisors of 2^33 - 1.at n=6A003540
- Divisors of 2^44 - 1.at n=16A003549
- a(n) = C(n,1) + C(n,2) + C(n,3), or n*(n^2 + 5)/6.at n=23A004006
- Number of nonzero coefficients of order n in Baker-Campbell-Hausdorff expansion.at n=13A005489
- Mersenne numbers with at most 2 prime factors.at n=4A006515
- Smallest odd composite number that requires n Miller-Rabin primality tests.at n=1A006945
- Euler pseudoprimes: composite numbers n such that 2^((n-1)/2) == +-1 (mod n).at n=5A006970