16401
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
- 27648
- Proper Divisor Sum (Aliquot Sum)
- 11247
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 8400
- Möbius Function
- 1
- Radical
- 16401
- 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
- 159
- 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(0) = 1, a(n) = 31*n^2 + 2 for n>0.at n=23A010020
- q-Catalan numbers (binomial version) for q=5.at n=3A015035
- Least m such that if r and s in {1/1, 1/3, 1/6,..., 1/C(n+1,2)} satisfy r < s, then r < k/m < s for some integer k.at n=43A024826
- Sums of 3 distinct powers of 4.at n=36A038471
- Sums of 5 distinct powers of 5.at n=9A038477
- The n-th n-gonal number: a(n) = n*(n^2 - 3*n + 4)/2.at n=33A060354
- Numbers k > 1 such that, in base 8, k and k^2 contain the same digits in the same proportion.at n=11A061662
- Centered 20-gonal (or icosagonal) numbers.at n=40A069133
- Smallest a(n)>a(n-1) such that a(n)^2+a(n-1)^2 is a perfect square, a(1)=6.at n=31A076672
- Smallest a(n)>a(n-1) such that a(n)^2+a(n-1)^2 is a perfect square, a(1)=7.at n=27A076673
- Smallest a(n)>a(n-1) such that a(n)^2+a(n-1)^2 is a perfect square, a(1)=10.at n=27A076675
- Smallest a(n)>a(n-1) such that a(n)^2+a(n-1)^2 is a perfect square, a(1)=11.at n=25A076676
- a(n) = 3*(a(n-2) + 1), with a(0) = 1, a(1) = 3.at n=16A087503
- Triangle T(n,k) giving number of (<=2)-covers of an n-set with k blocks.at n=39A094573
- Triangle read by rows: T(n,k) = (n+1,k)-th element of (M^5-M)/4, where M is the infinite lower Pascal's triangle matrix, 1<=k<=n.at n=23A096039
- 33-gonal numbers: n(31n-29)/2.at n=33A098923
- Sum of first 2n primes.at n=42A109722
- Negative numbers written in a bits-of-Pi/primorial base system.at n=6A109839
- Number of partitions of n such that if k is the largest part, then k-2 occurs as a part.at n=44A119907
- Expansion of x*(1+x+2*x^3) / ((x-1)*(1+x)*(3*x^2-1)).at n=18A120463