821889 has 24 divisors (see below), whose sum is σ = 1272960. Its totient is φ = 510048.

The previous prime is 821879. The next prime is 821897. The reversal of 821889 is 988128.

It is not a de Polignac number, because 821889 - 2⁵ = 821857 is a prime.

It is a Curzon number.

821889 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (821809) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12234 + ... + 12300.

It is an arithmetic number, because the mean of its divisors is an integer number (53040).

2⁸²¹⁸⁸⁹ is an apocalyptic number.

It is an amenable number.

821889 is a deficient number, since it is larger than the sum of its proper divisors (451071).

821889 is a wasteful number, since it uses less digits than its factorization.

821889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 149 (or 146 counting only the distinct ones).

The product of its digits is 9216, while the sum is 36.

The square root of 821889 is about 906.5809395746. The cubic root of 821889 is about 93.6708345023.

The spelling of 821889 in words is "eight hundred twenty-one thousand, eight hundred eighty-nine".