12139
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 16
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 12400
- Proper Divisor Sum (Aliquot Sum)
- 261
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 11880
- Möbius Function
- 1
- Radical
- 12139
- 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
- 50
- 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
- Numerators of coefficients in Taylor series expansion of log(1+x)^2/sqrt(1+x).at n=5A002551
- a(1) = 3; for n>0, a(n+1) = a(n) + floor((a(n)-1)/2).at n=22A003312
- 4th elementary symmetric function of the first n+3 odd positive integers.at n=2A024198
- Triangle of coefficients in expansion of (x+1)*(x+3)*...*(x + 2n - 1) in rising powers of x.at n=23A028338
- Coefficient of x^2 in expansion of (x+1)*(x+3)*...*(x+2*n-1).at n=4A028339
- Triangle of coefficients in expansion of (x-1)*(x-3)*(x-5)*...*(x-(2*n-1)).at n=23A039757
- Triangle of B-analogs of Stirling numbers of first kind.at n=25A039758
- Number of partitions satisfying 0 < cn(1,5) + cn(2,5) + cn(3,5) and 0 < cn(4,5) + cn(2,5) + cn(3,5).at n=34A039901
- Number of 3-noncrossing restricted RNA structures with n vertices.at n=11A103140
- Triangle of coefficients in expansion of (1+x)*(1+3x)*(1+5x)*(1+7x)*...*(1+(2n-1)x).at n=25A109692
- a(n) = 42*n^2 + 1.at n=17A158604
- Number of n X n symmetric binary arrays with rows, considered as binary numbers, in nondecreasing order, and all but the outermost 2 rows or columns zero.at n=4A162028
- Numbers k that are the products of two distinct primes such that 2*k-1, 4*k-3, 8*k-7, 16*k-15 and 32*k-31 are also products of two distinct primes.at n=20A177214
- Numbers k that are the products of two distinct primes such that 2*k-1, 4*k-3, 8*k-7, 16*k-15, 32*k-31 and 64*k-63 are also products of two distinct primes.at n=7A177215
- Numbers k that are the products of two distinct primes such that 2*k-1, 4*k-3, 8*k-7, 16*k-15, 32*k-31, 64*k-63 and 128*k-127 are also products of two distinct primes.at n=1A177216
- [s(k)-s(j)]/10, where the pairs (k,j) are given by A205877 and A205878, and s(k) denotes the (k+1)-st Fibonacci number.at n=25A205880
- Numerator of Sum_{k=1..n} 1/lambda(k), where lambda(k) is the Carmichael's lambda function.at n=25A211306
- a(n) = 7*n^2 - 5*n + 1.at n=42A239449
- Triangular matrix T defined by T = exp(L) where L(n,k) = C(2*n, 2*k+1)/2, as read by rows n >= 0, k=0..n.at n=31A246381
- Number of partitions of n into two sorts of parts having exactly 4 parts of the second sort.at n=11A258474