989909989 has 4 divisors (see below), whose sum is σ = 999711180. Its totient is φ = 980108800.

The previous prime is 989909981. The next prime is 989909993.

989909989 is nontrivially palindromic in base 10.

989909989 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 530150625 + 459759364 = 23025^2 + 21442^2 .

It is a cyclic number.

It is not a de Polignac number, because 989909989 - 2³ = 989909981 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (989909981) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4900444 + ... + 4900645.

It is an arithmetic number, because the mean of its divisors is an integer number (249927795).

Almost surely, 2^989909989 is an apocalyptic number.

It is an amenable number.

989909989 is a deficient number, since it is larger than the sum of its proper divisors (9801191).

989909989 is a wasteful number, since it uses less digits than its factorization.

989909989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9801190.

The product of its (nonzero) digits is 34012224, while the sum is 70.

The square root of 989909989 is about 31462.8350439054. The cubic root of 989909989 is about 996.6252871242.

The spelling of 989909989 in words is "nine hundred eighty-nine million, nine hundred nine thousand, nine hundred eighty-nine".