15617
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 18816
- Proper Divisor Sum (Aliquot Sum)
- 3199
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 12672
- Möbius Function
- -1
- Radical
- 15617
- 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
- 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
- no
- Odd
- yes
Appears in sequences
- a(n) = n^3 - floor( n/3 ).at n=25A002901
- E.g.f. exp(sin(x)*exp(x)).at n=8A009212
- Square root of A030693.at n=28A030694
- Gaps of 7 in sequence A038593 (lower terms).at n=37A038653
- Gaps of 9 in sequence A038593 (upper terms).at n=10A038658
- "Orderly" Friedman numbers (or "good" or "nice" Friedman numbers): Friedman numbers (A036057) where the construction digits are used in the proper order.at n=23A080035
- Numbers n for which 2*R_n + 1 is a prime, where R_n = 11...1 is the repunit (A002275) of length n.at n=19A096506
- Triangle read by rows: T(n,1) = 1, T(n,n) = n and for 1 < k < n: T(n,k) = T(n-1,k-1) + 2*T(n-1,k).at n=59A105728
- a(n) = (3*n+1)*(5*n+1).at n=32A144459
- 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, 0), (-1, 0, 0), (0, 0, -1), (0, 1, 1), (1, -1, 1)}.at n=9A148835
- Products of three distinct happy primes A035497.at n=21A154717
- 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=3A156954
- 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=5A157198
- Monotonic ordering of nonnegative differences 5^i-8^j, for 40>= i>=0, j>=0.at n=18A192197
- Friedman numbers n such that n+1 is also a Friedman number.at n=33A195420
- Smallest number k such that k^2 begins with n^3.at n=28A197722
- a(n) = 384*n + 257.at n=40A229855
- Number of length 3 0..n arrays with each partial sum starting from the beginning no more than one standard deviation from its mean.at n=33A244791
- a(n) = n^3 - 8.at n=25A259348
- Number of n X n 0..1 arrays with every element unequal to 0, 1 or 3 king-move adjacent elements, with upper left element zero.at n=11A303676