821889689 has 2 divisors, whose sum is σ = 821889690. Its totient is φ = 821889688.

The previous prime is 821889683. The next prime is 821889749. The reversal of 821889689 is 986988128.

821889689 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 440664064 + 381225625 = 20992^2 + 19525^2 .

It is a cyclic number.

It is not a de Polignac number, because 821889689 - 2⁸ = 821889433 is a prime.

It is not a weakly prime, because it can be changed into another prime (821889683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410944844 + 410944845.

It is an arithmetic number, because the mean of its divisors is an integer number (410944845).

Almost surely, 2^821889689 is an apocalyptic number.

It is an amenable number.

821889689 is a deficient number, since it is larger than the sum of its proper divisors (1).

821889689 is an equidigital number, since it uses as much as digits as its factorization.

821889689 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3981312, while the sum is 59.

The square root of 821889689 is about 28668.6185401390. The cubic root of 821889689 is about 936.7086067742.

The spelling of 821889689 in words is "eight hundred twenty-one million, eight hundred eighty-nine thousand, six hundred eighty-nine".