15006
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 12
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 31248
- Proper Divisor Sum (Aliquot Sum)
- 16242
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4800
- Möbius Function
- 1
- Radical
- 15006
- 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
- yes
Recreational
- Happy Number
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 63
- 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
- a(0) = 1, a(n) = 31*n^2 + 2 for n>0.at n=22A010020
- Convolution of natural numbers >= 2 and natural numbers >= 3.at n=40A023545
- Smallest number m such that m^2+1 is divisible by A002144(n)^2 (= squares of primes congruent to 1 mod 4).at n=23A059321
- Numbers which are the sum of their proper divisors containing the digit 5.at n=16A059464
- Numbers n such that the n-th prime - n is a cube.at n=10A105645
- 4-almost primes equal to the product of two successive semiprimes.at n=40A108215
- Numbers n such that prime(n) - n is a prime power.at n=18A109315
- Intersection of A002378 and A135013.at n=4A135014
- Product of the n-th run of squarefree numbers.at n=33A136742
- 6 times pentagonal numbers: a(n) = 3*n*(3*n-1).at n=41A152743
- a(n) = the smallest k such that k^2+1 = p*A002144(n)^2, p prime of A002144 .at n=23A174492
- a(n) = 25*n^2 + 25*n + 6.at n=24A177059
- a(n) = (7*n + 3)*(7*n + 4).at n=17A177071
- Golden Triangle sums: a(n)=a(n-2)+A001654(n) with a(0)=0 and a(1)=1.at n=11A180665
- Number of (n+2) X 5 binary arrays avoiding patterns 001 and 110 in rows, columns and nw-to-se diagonals.at n=11A202442
- Nonnegative integers whose English number-words have the identical number of letters contributing to each represented letter-frequency.at n=61A216163
- Squarefree oblong numbers.at n=42A229882
- a(n) = (4*n+3)*(4*n+2).at n=30A256833
- Numbers n such that n^2 + 1 has two distinct prime divisors less than n.at n=21A263876
- Consider a number x > 1. Take the sum of its digits. Repeat the process deleting the first addendum and adding the previous sum. The sequence lists the numbers that after some iterations reach the Euler totient function of x.at n=20A269310