1989765009 has 6 divisors (see below), whose sum is σ = 2874105026. Its totient is φ = 1326510000.

The previous prime is 1989764993. The next prime is 1989765013. The reversal of 1989765009 is 9005679891.

It can be written as a sum of positive squares in only one way, i.e., 1977758784 + 12006225 = 44472^2 + 3465^2 .

It is not a de Polignac number, because 1989765009 - 2⁴ = 1989764993 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1989765049) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 110542492 + ... + 110542509.

Almost surely, 2^1989765009 is an apocalyptic number.

It is an amenable number.

1989765009 is a deficient number, since it is larger than the sum of its proper divisors (884340017).

1989765009 is a wasteful number, since it uses less digits than its factorization.

1989765009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221085007 (or 221085004 counting only the distinct ones).

The product of its (nonzero) digits is 1224720, while the sum is 54.

The square root of 1989765009 is about 44606.7820964481. The cubic root of 1989765009 is about 1257.7681598049.

The spelling of 1989765009 in words is "one billion, nine hundred eighty-nine million, seven hundred sixty-five thousand, nine".