831861872821 has 4 divisors (see below), whose sum is σ = 950699283232. Its totient is φ = 713024462412.

The previous prime is 831861872813. The next prime is 831861872861. The reversal of 831861872821 is 128278168138.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 831861872821 - 2³ = 831861872813 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 (831861872861) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 59418705195 + ... + 59418705208.

It is an arithmetic number, because the mean of its divisors is an integer number (237674820808).

Almost surely, 2^831861872821 is an apocalyptic number.

It is an amenable number.

831861872821 is a deficient number, since it is larger than the sum of its proper divisors (118837410411).

831861872821 is a wasteful number, since it uses less digits than its factorization.

831861872821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 118837410410.

The product of its digits is 2064384, while the sum is 55.

The spelling of 831861872821 in words is "eight hundred thirty-one billion, eight hundred sixty-one million, eight hundred seventy-two thousand, eight hundred twenty-one".