Number of the day: 9821

Properties of the number 9821:

9821 is a cyclic number.
9821 = 7 × 23 × 61 is a sphenic number and squarefree.
9821 has 3 distinct prime factors, 8 divisors, 11 antidivisors and 7920 totatives.
9821 has an oblong digit sum 20 in base 10.
9821 has a Fibonacci digit product 144 in base 10.
Reversing the decimal digits of 9821 results in a prime.
9821 = 4911² - 4910² = 705² - 698² = 225² - 202² = 111² - 50² is the difference of 2 nonnegative squares in 4 ways.
9821 is the sum of 2 positive triangular numbers.
9821 is the difference of 2 positive pentagonal numbers in 3 ways.
9821 = 11² + 40² + 90² is the sum of 3 positive squares.
9821² = 1771² + 9660² is the sum of 2 positive squares in 1 way.
9821² is the sum of 3 positive squares.
9821 is a proper divisor of 47⁶ - 1.
9821 is palindromic in (at least) base -30.
9821 in base 29 = bjj and consists of only the digits 'b' and 'j'.
9821 in base 49 = 44L and consists of only the digits '4' and 'L'.

The number 9821 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A028910: Arrange digits of 2^n in descending order.
A042085: Denominators of continued fraction convergents to sqrt(566).
A050817: Odd numbers seen in decimal expansion of pi (disregarding the decimal period) contiguous, smallest and distinct.
A066509: a(n) is the first of a triple of consecutive integers, each the product of three distinct primes.
A077325: Average of terms of n-th row of A077321.
A081677: Numbers n such that 2*10^n + 3 is prime.
A204663: Numbers n such that n!8 + 2 is prime.
A232206: Triangle read by rows: T(n,k) is the number of non-equivalent regular polygons with n+1 edges, one of which is rooted, which are dissected by non-intersecting diagonals into k regions, such that two such polygons are identified up to reflection along the rooted edge and twisting along the diagonals that does not affect the root edge (for 1 <= k <= n-1 and n>=2).
A244242: Number of partitions of n into 6 parts such that every i-th smallest part (counted with multiplicity) is different from i.
A286006: Numbers n such that 11^n is the highest power of 11 dividing A240751(n).