987989789 has 4 divisors (see below), whose sum is σ = 988486524. Its totient is φ = 987493056.

The previous prime is 987989693. The next prime is 987989791.

987989789 is nontrivially palindromic in base 10.

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 325802500 + 662187289 = 18050^2 + 25733^2 .

It is a cyclic number.

It is not a de Polignac number, because 987989789 - 2²⁰ = 986941213 is a prime.

It is a super-2 number, since 2×987989789² = 1952247646336529042, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (987986789) 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 3 ways as a sum of consecutive naturals, for example, 245372 + ... + 249365.

It is an arithmetic number, because the mean of its divisors is an integer number (247121631).

Almost surely, 2^987989789 is an apocalyptic number.

It is an amenable number.

987989789 is a deficient number, since it is larger than the sum of its proper divisors (496735).

987989789 is a wasteful number, since it uses less digits than its factorization.

987989789 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 496734.

The product of its digits is 164602368, while the sum is 74.

The square root of 987989789 is about 31432.3048629909. The cubic root of 987989789 is about 995.9804612894.

The spelling of 987989789 in words is "nine hundred eighty-seven million, nine hundred eighty-nine thousand, seven hundred eighty-nine".