2021731021 has 4 divisors (see below), whose sum is σ = 2024512672. Its totient is φ = 2018949372.

The previous prime is 2021731013. The next prime is 2021731037. The reversal of 2021731021 is 1201371202.

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 2021731021 - 2³ = 2021731013 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2021731021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2021731091) 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, 1389735 + ... + 1391188.

It is an arithmetic number, because the mean of its divisors is an integer number (506128168).

Almost surely, 2^2021731021 is an apocalyptic number.

It is an amenable number.

2021731021 is a deficient number, since it is larger than the sum of its proper divisors (2781651).

2021731021 is an equidigital number, since it uses as much as digits as its factorization.

2021731021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2781650.

The product of its (nonzero) digits is 168, while the sum is 19.

The square root of 2021731021 is about 44963.6633405242. The cubic root of 2021731021 is about 1264.4678501397.

The spelling of 2021731021 in words is "two billion, twenty-one million, seven hundred thirty-one thousand, twenty-one".