816661839 has 16 divisors (see below), whose sum is σ = 1264839680. Its totient is φ = 459012960.

The previous prime is 816661757. The next prime is 816661871. The reversal of 816661839 is 938166618.

816661839 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 816661839 - 2⁷ = 816661711 is a prime.

It is a Smith number, since the sum of its digits (48) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (816661889) 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, 317479 + ... + 320040.

It is an arithmetic number, because the mean of its divisors is an integer number (79052480).

Almost surely, 2^816661839 is an apocalyptic number.

816661839 is a deficient number, since it is larger than the sum of its proper divisors (448177841).

816661839 is a wasteful number, since it uses less digits than its factorization.

816661839 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 637590.

The product of its digits is 373248, while the sum is 48.

The square root of 816661839 is about 28577.2958657743. The cubic root of 816661839 is about 934.7183186866.

The spelling of 816661839 in words is "eight hundred sixteen million, six hundred sixty-one thousand, eight hundred thirty-nine".