861798391 has 12 divisors (see below), whose sum is σ = 930085632. Its totient is φ = 795756416.

The previous prime is 861798383. The next prime is 861798397. The reversal of 861798391 is 193897168.

It is a happy number.

It is not a de Polignac number, because 861798391 - 2³ = 861798383 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 (861798397) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 38730 + ... + 56776.

It is an arithmetic number, because the mean of its divisors is an integer number (77507136).

Almost surely, 2^861798391 is an apocalyptic number.

861798391 is a deficient number, since it is larger than the sum of its proper divisors (68287241).

861798391 is a wasteful number, since it uses less digits than its factorization.

861798391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18170 (or 18117 counting only the distinct ones).

The product of its digits is 653184, while the sum is 52.

The square root of 861798391 is about 29356.4028961315. The cubic root of 861798391 is about 951.6309531444.

The spelling of 861798391 in words is "eight hundred sixty-one million, seven hundred ninety-eight thousand, three hundred ninety-one".