1989644089 has 2 divisors, whose sum is σ = 1989644090. Its totient is φ = 1989644088.

The previous prime is 1989644087. The next prime is 1989644143. The reversal of 1989644089 is 9804469891.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1370480400 + 619163689 = 37020^2 + 24883^2 .

It is a cyclic number.

It is not a de Polignac number, because 1989644089 - 2¹ = 1989644087 is a prime.

Together with 1989644087, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1989644087) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 994822044 + 994822045.

It is an arithmetic number, because the mean of its divisors is an integer number (994822045).

Almost surely, 2^1989644089 is an apocalyptic number.

It is an amenable number.

1989644089 is a deficient number, since it is larger than the sum of its proper divisors (1).

1989644089 is an equidigital number, since it uses as much as digits as its factorization.

1989644089 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4478976, while the sum is 58.

The square root of 1989644089 is about 44605.4266765827. The cubic root of 1989644089 is about 1257.7426806811.

The spelling of 1989644089 in words is "one billion, nine hundred eighty-nine million, six hundred forty-four thousand, eighty-nine".