861839391 has 24 divisors (see below), whose sum is σ = 1339759920. Its totient is φ = 491363712.

The previous prime is 861839383. The next prime is 861839443. The reversal of 861839391 is 193938168.

It is not a de Polignac number, because 861839391 - 2³ = 861839383 is a prime.

It is a hoax number, since the sum of its digits (48) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 861839391.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861835391) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 60765 + ... + 73593.

It is an arithmetic number, because the mean of its divisors is an integer number (55823330).

Almost surely, 2^861839391 is an apocalyptic number.

861839391 is a deficient number, since it is larger than the sum of its proper divisors (477920529).

861839391 is a wasteful number, since it uses less digits than its factorization.

861839391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13303 (or 13296 counting only the distinct ones).

The product of its digits is 279936, while the sum is 48.

The square root of 861839391 is about 29357.1012022645. The cubic root of 861839391 is about 951.6460441644.

The spelling of 861839391 in words is "eight hundred sixty-one million, eight hundred thirty-nine thousand, three hundred ninety-one".