809999988 has 96 divisors (see below), whose sum is σ = 2231577600. Its totient is φ = 228543840.

The previous prime is 809999959. The next prime is 809999989. The reversal of 809999988 is 889999908.

809999988 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (809999989) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 340443 + ... + 342813.

It is an arithmetic number, because the mean of its divisors is an integer number (23245600).

Almost surely, 2^809999988 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 809999988, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1115788800).

809999988 is an abundant number, since it is smaller than the sum of its proper divisors (1421577612).

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

809999988 is a wasteful number, since it uses less digits than its factorization.

809999988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2482 (or 2466 counting only the distinct ones).

The product of its (nonzero) digits is 30233088, while the sum is 69.

The square root of 809999988 is about 28460.4987306969. The cubic root of 809999988 is about 932.1697471829.

The spelling of 809999988 in words is "eight hundred nine million, nine hundred ninety-nine thousand, nine hundred eighty-eight".