9899779988 has 48 divisors (see below), whose sum is σ = 20853168000. Its totient is φ = 4017237120.

The previous prime is 9899779961. The next prime is 9899780003. The reversal of 9899779988 is 8899779989.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1241438 + ... + 1249386.

It is an arithmetic number, because the mean of its divisors is an integer number (434441000).

Almost surely, 2^9899779988 is an apocalyptic number.

It is an amenable number.

9899779988 is an abundant number, since it is smaller than the sum of its proper divisors (10953388012).

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

9899779988 is a wasteful number, since it uses less digits than its factorization.

9899779988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10320 (or 10318 counting only the distinct ones).

The product of its digits is 1481421312, while the sum is 83.

The square root of 9899779988 is about 99497.6381026203. The cubic root of 9899779988 is about 2147.2132626323.

Subtracting from 9899779988 its reverse (8899779989), we obtain a palindrome (999999999).

The spelling of 9899779988 in words is "nine billion, eight hundred ninety-nine million, seven hundred seventy-nine thousand, nine hundred eighty-eight".