Number of the day: 9913

Properties of the number 9913:

9913 is a cyclic number.
9913 = 23 × 431 is semiprime and squarefree.
9913 has 2 distinct prime factors, 4 divisors, 17 antidivisors and 9460 totatives.
9913 has a semiprime digit sum 22 in base 10.
Reversing the decimal digits of 9913 results in an emirpimes.
9913 = 4957² - 4956² = 227² - 204² is the difference of 2 nonnegative squares in 2 ways.
9913 is the difference of 2 positive pentagonal numbers in 2 ways.
9913 = 16² + 51² + 84² is the sum of 3 positive squares.
9913² is the sum of 3 positive squares.
9913 is a proper divisor of 863¹¹ - 1.
9913 = '991' + '3' is the concatenation of 2 prime numbers.
9913 = '9' + '913' is the concatenation of 2 semiprime numbers.
9913 is an emirpimes in (at least) the following bases: 2, 3, 4, 6, 7, 8, 9, 10, 12, 14, 16, 19, 24, 25, 29, 32, 37, 41, 44, 45, 52, 59, 65, 66, 73, 74, 77, 80, 81, 85, 87, 91, 92, 96, 97, 98, and 99.
9913 is palindromic in (at least) the following bases: 35, 84, and -39.
9913 in base 21 = 11a1 and consists of only the digits '1' and 'a'.
9913 in base 34 = 8jj and consists of only the digits '8' and 'j'.
9913 in base 35 = 838 and consists of only the digits '3' and '8'.
9913 in base 44 = 55D and consists of only the digits '5' and 'D'.

The number 9913 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A007811: Numbers n for which 10n+1, 10n+3, 10n+7 and 10n+9 are primes.
A080697: a(n) = n * prime(prime(n)).
A118367: Largest number that is not the sum of five n-gonal numbers.
A208807: Number of n-bead necklaces labeled with numbers -1..1 not allowing reversal, with sum zero and three times sum of squares <= n*(1)*(1+1).
A233585: Coefficients of the generalized continued fraction expansion of the inverse of Euler constant, 1/gamma = a(1) +a(1)/(a(2) +a(2)/(a(3) +a(3)/(a(4) +a(4)/....))).
A244791: Number of length 3 0..n arrays with each partial sum starting from the beginning no more than one standard deviation from its mean.
A256533: Product of n and the sum of all divisors of all positive integers <= n.
A270893: Partial sums of the number of active (ON,black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 209", based on the 5-celled von Neumann neighborhood.
A284648: Numerator of sum of reciprocals of all divisors of all positive integers <= n.
A331453: Triangle read by rows: T(n,m) (n >= m >= 1) = number of vertices formed by drawing the lines connecting any two of the 2*(m+n) perimeter points of an m X n grid of squares.