89821 has 2 divisors, whose sum is σ = 89822. Its totient is φ = 89820.

The previous prime is 89819. The next prime is 89833. The reversal of 89821 is 12898.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 55225 + 34596 = 235^2 + 186^2 .

It is a cyclic number.

It is not a de Polignac number, because 89821 - 2¹ = 89819 is a prime.

Together with 89819, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 89821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (89891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 44910 + 44911.

It is an arithmetic number, because the mean of its divisors is an integer number (44911).

2⁸⁹⁸²¹ is an apocalyptic number.

It is an amenable number.

89821 is a deficient number, since it is larger than the sum of its proper divisors (1).

89821 is an equidigital number, since it uses as much as digits as its factorization.

89821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1152, while the sum is 28.

The square root of 89821 is about 299.7015181810. The cubic root of 89821 is about 44.7843176934.

It can be divided in two parts, 898 and 21, that added together give a palindrome (919).

The spelling of 89821 in words is "eighty-nine thousand, eight hundred twenty-one".