809898989 has 8 divisors (see below), whose sum is σ = 873721080. Its totient is φ = 747874816.

The previous prime is 809898983. The next prime is 809899007. The reversal of 809898989 is 989898908.

It can be written as a sum of positive squares in 4 ways, for example, as 438064900 + 371834089 = 20930^2 + 19283^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 809898989 - 2²⁴ = 793121773 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (809898983) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 448544 + ... + 450345.

It is an arithmetic number, because the mean of its divisors is an integer number (109215135).

Almost surely, 2^809898989 is an apocalyptic number.

It is an amenable number.

809898989 is a deficient number, since it is larger than the sum of its proper divisors (63822091).

809898989 is a wasteful number, since it uses less digits than its factorization.

809898989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 898959.

The product of its (nonzero) digits is 26873856, while the sum is 68.

The square root of 809898989 is about 28458.7243038053. The cubic root of 809898989 is about 932.1310014515.

The spelling of 809898989 in words is "eight hundred nine million, eight hundred ninety-eight thousand, nine hundred eighty-nine".