816897839 has 4 divisors (see below), whose sum is σ = 845066760. Its totient is φ = 788728920.

The previous prime is 816897827. The next prime is 816897859. The reversal of 816897839 is 938798618.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 816897839 - 2²⁰ = 815849263 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (816897859) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14084417 + ... + 14084474.

It is an arithmetic number, because the mean of its divisors is an integer number (211266690).

Almost surely, 2^816897839 is an apocalyptic number.

816897839 is a deficient number, since it is larger than the sum of its proper divisors (28168921).

816897839 is a wasteful number, since it uses less digits than its factorization.

816897839 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28168920.

The product of its digits is 5225472, while the sum is 59.

The square root of 816897839 is about 28581.4247195622. The cubic root of 816897839 is about 934.8083487198.

The spelling of 816897839 in words is "eight hundred sixteen million, eight hundred ninety-seven thousand, eight hundred thirty-nine".