809991867 has 16 divisors (see below), whose sum is σ = 1096214688. Its totient is φ = 531901440.

The previous prime is 809991829. The next prime is 809991881. The reversal of 809991867 is 768199908.

It is not a de Polignac number, because 809991867 - 2¹² = 809987771 is a prime.

It is a super-2 number, since 2×809991867² = 1312173649212291378, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (809991887) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 206767 + ... + 210647.

It is an arithmetic number, because the mean of its divisors is an integer number (68513418).

Almost surely, 2^809991867 is an apocalyptic number.

809991867 is a deficient number, since it is larger than the sum of its proper divisors (286222821).

809991867 is a wasteful number, since it uses less digits than its factorization.

809991867 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4910.

The product of its (nonzero) digits is 1959552, while the sum is 57.

The square root of 809991867 is about 28460.3560589111. The cubic root of 809991867 is about 932.1666318841.

The spelling of 809991867 in words is "eight hundred nine million, nine hundred ninety-one thousand, eight hundred sixty-seven".