15618
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 33120
- Proper Divisor Sum (Aliquot Sum)
- 17502
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4896
- Möbius Function
- 1
- Radical
- 15618
- Omega Function (Ω)
- 4
- Little Omega Function (ω)
- 4
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
- 146
- 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
- Ordered sequence of distinct terms of the form floor(x^i * floor(x^j)), i,j >= 0, where x = sqrt(5).at n=38A022770
- Number of binary [ n,3 ] codes without 0 columns.at n=30A034344
- Multiplicity of highest weight (or singular) vectors associated with character chi_137 of Monster module.at n=40A034525
- Number of permutations p(1),...,p(n) of 1,...,n such that gcd(Sum_{k=1..m} p(k), p(m+1)) = 1 for all positive integers m <= n-1.at n=8A076143
- "Orderly" Friedman numbers (or "good" or "nice" Friedman numbers): Friedman numbers (A036057) where the construction digits are used in the proper order.at n=24A080035
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 1), (-1, 1, -1), (0, 1, 1), (1, 0, 0), (1, 0, 1)}.at n=7A151083
- Integers N such that by inserting + or - or * or / or ^ between each of their digits, without any grouping parentheses, you can get N (the ambiguous a^b^c is avoided).at n=4A156954
- Integers n such that by inserting between their digits + or - or * or / or ^ or nothing (i.e., concatenate two digits) you recover n back in a nontrivial way.at n=6A157198
- Irregular triangle of coefficients of p(n, x) = (1 - x^2)^(n+1)*Sum_{j >= 0} (4*j+ 1)^n*x^(2*j), read by rows.at n=38A158782
- Monotonic ordering of nonnegative differences 5^i-7^j, for 40>= i>=0, j>=0.at n=19A192195
- Triangle read by rows, coefficients of the generalized Eulerian polynomials A_{n, 4}(x) in descending order.at n=26A225118
- Bases b for which there exists an integer y such that y^3 in base b looks like [c,d,c,d] for some base-b digits c, d.at n=41A290176
- Sum of all the parts in the partitions of n into 4 parts.at n=38A308775
- Number of integer compositions of n with all distinct runs.at n=17A351013
- Numbers that can be represented using their digits in the order of appearance, the operations +, -, *, /, ^, and any parentheses.at n=25A386936