809309840 has 20 divisors (see below), whose sum is σ = 1881645564. Its totient is φ = 323723904.

The previous prime is 809309821. The next prime is 809309909. The reversal of 809309840 is 48903908.

It can be written as a sum of positive squares in 2 ways, for example, as 169624576 + 639685264 = 13024^2 + 25292^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5058107 + ... + 5058266.

Almost surely, 2^809309840 is an apocalyptic number.

809309840 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

809309840 is an abundant number, since it is smaller than the sum of its proper divisors (1072335724).

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

809309840 is a wasteful number, since it uses less digits than its factorization.

809309840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10116386 (or 10116380 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 41.

The square root of 809309840 is about 28448.3714823889. The cubic root of 809309840 is about 931.9049250029.

The spelling of 809309840 in words is "eight hundred nine million, three hundred nine thousand, eight hundred forty".