13157
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 17
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 13440
- Proper Divisor Sum (Aliquot Sum)
- 283
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 12876
- Möbius Function
- 1
- Radical
- 13157
- 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
- 138
- 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) = floor( n*(n-1)*(n-2)/19 ).at n=64A011901
- Numbers k such that the continued fraction for sqrt(k) has period 98.at n=18A020437
- Number of ways to partition n labeled elements into pie slices of different odd sizes, allowing the pie to be turned over.at n=13A032220
- Number of ways to partition n labeled elements into sets of odd sizes, with all sizes different.at n=13A032310
- a(n) = Sum_{i=0..n} T(i,n-i), array T as in A049747.at n=34A049748
- Coefficients of replicable function number 12b.at n=12A058490
- Numbers k such that k + prime(k) gives a triangular number.at n=43A115882
- 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, 0, 0), (0, -1, 1), (1, 1, 0), (1, 1, 1)}.at n=7A150924
- Expansion of (chi(q^3) / chi(q))^6 + q / (chi(q^3) / chi(q))^6 in powers of q where chi() is a Ramanujan theta function.at n=12A156215
- Number of n X 2 0..1 arrays with rows, columns and antidiagonals unimodal and diagonals nondecreasing.at n=21A223764
- Volume of Johnson square pyramid placed upright on cube (rounded down) with edge lengths equal to n.at n=21A227221
- Number of partitions of n such that (number parts having multiplicity 1) is a part and (number of 1s) is not a part.at n=40A241508
- Number of length 4 0..n arrays with each partial sum starting from the beginning no more than two standard deviations from its mean.at n=9A244835
- a(n) is the sum of quadratic nonresidues of A002145(n) (the n-th prime == 3 mod 4).at n=25A282036
- Let p = n-th prime == 7 mod 8; a(n) = sum of quadratic nonresidues mod p.at n=12A282043
- Number of n X 6 0..1 arrays with every element unequal to 1, 2, 5, 6 or 7 king-move adjacent elements, with upper left element zero.at n=9A305180
- a(n) = n*(n + 5)*(n + 7)/6 + 1.at n=39A323221