2109331721 has 24 divisors (see below), whose sum is σ = 2576710080. Its totient is φ = 1686798432.

The previous prime is 2109331711. The next prime is 2109331723. The reversal of 2109331721 is 1271339012.

It is not a de Polignac number, because 2109331721 - 2⁶ = 2109331657 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2109331723) 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, 595271 + ... + 598803.

It is an arithmetic number, because the mean of its divisors is an integer number (107362920).

Almost surely, 2^2109331721 is an apocalyptic number.

It is an amenable number.

2109331721 is a deficient number, since it is larger than the sum of its proper divisors (467378359).

2109331721 is an equidigital number, since it uses as much as digits as its factorization.

2109331721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3693 (or 3626 counting only the distinct ones).

The product of its (nonzero) digits is 2268, while the sum is 29.

The square root of 2109331721 is about 45927.4615126941. The cubic root of 2109331721 is about 1282.4731888602.

The spelling of 2109331721 in words is "two billion, one hundred nine million, three hundred thirty-one thousand, seven hundred twenty-one".