2855
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 3432
- Proper Divisor Sum (Aliquot Sum)
- 577
- 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
- 2280
- Möbius Function
- 1
- Radical
- 2855
- 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
- 128
- 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
- Number of partitions into non-integral powers.at n=25A000148
- Smallest number of complexity n: smallest number requiring n 1's to build using +, * and ^.at n=21A003037
- Coordination sequence T2 for Zeolite Code AFS.at n=41A008024
- Coordination sequence T1 for Zeolite Code MFI.at n=34A008161
- Number of labeled servers of dimension 5.at n=4A027392
- Number of partitions of n into parts not of the form 9k, 9k+2 or 9k-2. Also number of partitions with 1 part of size 1 and differences between parts at distance 3 are greater than 1.at n=36A035941
- Numbers n such that string 2,2 occurs in the base 9 representation of n but not of n-1.at n=35A044271
- Numbers n such that string 5,5 occurs in the base 10 representation of n but not of n-1.at n=28A044387
- Numbers n such that string 2,2 occurs in the base 9 representation of n but not of n+1.at n=35A044652
- Numbers n such that string 5,5 occurs in the base 10 representation of n but not of n+1.at n=28A044768
- Numbers whose base-3 representation contains exactly three 0's and four 2's.at n=30A045008
- a(n) = a(1) + a(2) + ... + a(n-1) - a(m) for n >= 3, where m = 2*n - 2 - 2^(p+1) and p is the unique integer such that 2^p < n-1 <= 2^(p+1), starting with a(1) = 1 and a(2) = 3.at n=14A049919
- Integer part of (Product(n^((1 + log(1 + i))/i^2), {i, 1, n})).at n=13A062486
- Nearest integer to (Product(n^((1 + log(1 + i))/i^2), {i, 1, n})).at n=13A062487
- Composite and every divisor (except 1) contains the digit 5.at n=23A062672
- Numbers k such that k divides the sum of digits of 8^k.at n=11A062933
- Frobenius number of the numerical semigroup generated by 3 consecutive triangular numbers.at n=13A069755
- Numbers k such that phi(phi(k)) = sum of prime factors of k.at n=10A075863
- Numbers k for which the sums of prime factors (ignoring multiplicity) of sigma(k) and phi(k) are equal but the sets of prime factors of sigma and phi are different.at n=6A081378
- Numbers of the form 2p+1, where p and p+2 are a pair of twin primes.at n=46A082496