831172021 has 8 divisors (see below), whose sum is σ = 834855840. Its totient is φ = 827496912.

The previous prime is 831172019. The next prime is 831172037. The reversal of 831172021 is 120271138.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 831172021 - 2¹ = 831172019 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 (831172061) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 248466 + ... + 251788.

It is an arithmetic number, because the mean of its divisors is an integer number (104356980).

Almost surely, 2^831172021 is an apocalyptic number.

It is an amenable number.

831172021 is a deficient number, since it is larger than the sum of its proper divisors (3683819).

831172021 is a wasteful number, since it uses less digits than its factorization.

831172021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4355.

The product of its (nonzero) digits is 672, while the sum is 25.

The square root of 831172021 is about 28830.0541275940. The cubic root of 831172021 is about 940.2217754222.

The spelling of 831172021 in words is "eight hundred thirty-one million, one hundred seventy-two thousand, twenty-one".