989999988 has 24 divisors (see below), whose sum is σ = 2347870560. Its totient is φ = 324589920.

The previous prime is 989999957. The next prime is 989999993. The reversal of 989999988 is 889999989.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 675498 + ... + 676961.

It is an arithmetic number, because the mean of its divisors is an integer number (97827940).

Almost surely, 2^989999988 is an apocalyptic number.

It is an amenable number.

989999988 is an abundant number, since it is smaller than the sum of its proper divisors (1357870572).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

989999988 is a wasteful number, since it uses less digits than its factorization.

989999988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1352527 (or 1352525 counting only the distinct ones).

The product of its digits is 272097792, while the sum is 78.

The square root of 989999988 is about 31464.2652544120. The cubic root of 989999988 is about 996.6554893857.

Subtracting from 989999988 its reverse (889999989), we obtain a palindrome (99999999).

The spelling of 989999988 in words is "nine hundred eighty-nine million, nine hundred ninety-nine thousand, nine hundred eighty-eight".