16161
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- yes
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 21552
- Proper Divisor Sum (Aliquot Sum)
- 5391
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 10772
- Möbius Function
- 1
- Radical
- 16161
- 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
- 146
- 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
- a(n+1) = Sum_{k=0..floor(3*n/5)} a(k) * a(n-k).at n=15A030038
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 84.at n=37A031582
- Palindromic Super-2 Numbers.at n=27A032750
- Period of 1/n in sequence A033938.at n=8A033939
- Numbers whose consecutive digits differ by 5.at n=37A048407
- Numbers n such that n and 2n+1 are both palindromes.at n=34A069881
- Palindromes k such that 3k + 1 is also a palindrome.at n=19A083829
- Palindromes with more than 3 digits in which the absolute difference of a pair of successive digits is identical.at n=19A085109
- Palindromes n such that 10n01 is a prime.at n=27A099744
- Indices of primes in sequence defined by A(0) = 53, A(n) = 10*A(n-1) + 43 for n > 0.at n=12A101585
- Form triangle shown below, in which the n-th row contains n terms of an arithmetic progression with first term 1 and common difference n. Then a(n) = terms of the n-th row (mod 10), concatenated.at n=4A110748
- Numbers n such that p(6n) is prime, where p(n) is the number of partitions of n.at n=34A111036
- Number of imprimitive (periodic) 2n-bead black-white reversible necklaces with n black beads.at n=33A115120
- Palindromic primes in base 9 (written in base 9).at n=25A117703
- Palindromes with odd number of digits formed from the reflected decimal expansion of golden ratio phi.at n=2A135699
- Palindromes formed from the reflected decimal expansion of golden ratio phi.at n=4A135700
- Numbers k such that k and k^2 use only the digits 1, 2, 6, 7 and 9.at n=13A137015
- a(n) = A000045(n) + A113405(n).at n=17A140428
- Ulam's spiral (ESE spoke).at n=32A143855
- 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, 0), (0, 0, 1), (1, 0, -1), (1, 0, 0)}.at n=8A150094