Number of the day: 983

Properties of the number 983:

983 is the 166^th prime.
983 has 9 antidivisors and 982 totatives.
983 has an oblong digit sum 20 in base 10.
Reversing the decimal digits of 983 results in an emirp.
983 = 492² - 491² is the difference of 2 nonnegative squares in 1 way.
983 is the difference of 2 positive pentagonal numbers in 1 way.
983 is not the sum of 3 positive squares.
983² is the sum of 3 positive squares.
983 is a divisor of 2⁴⁹¹ - 1.
983 is an emirp in (at least) the following bases: 3, 4, 5, 8, 9, 10, 11, 13, 14, 15, 16, 19, 21, 23, 24, 25, 27, 28, 31, 33, 38, 39, 41, 43, 49, 50, 51, 55, 56, 61, 62, 64, 69, 71, 74, 75, 79, 82, 83, 84, 85, 87, 89, and 91.
983 is palindromic in (at least) base -20.
983 in base 4 = 33113 and consists of only the digits '1' and '3'.

The number 983 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A000057: Primes dividing all Fibonacci sequences.
A001190: Wedderburn-Etherington numbers: unlabeled binary rooted trees (every node has out-degree 0 or 2) with n endpoints (and 2n-1 nodes in all).
A001913: Full reptend primes: primes with primitive root 10.
A005385: Safe primes p: (p-1)/2 is also prime.
A006567: Emirps (primes whose reversal is a different prime).
A007500: Primes whose reversal in base 10 is also prime (called "palindromic primes" by D. Wells, although that name usually refers to A002385). Also called reversible primes.
A007522: Primes of the form 8n+7, that is, primes congruent to -1 mod 8.
A141112: Primes of the form 2*x^2+5*x*y-5*y^2 (as well as of the form 7*x^2+11*x*y+2*y^2).
A152079: Primes p such that A000695(p) are also prime.
A191426: Dispersion of (3+[nr]), where r=(golden ratio)=(1+sqrt(5))/2 and [ ]=floor, by antidiagonals.