2008991721 has 16 divisors (see below), whose sum is σ = 2926676160. Its totient is φ = 1215693120.

The previous prime is 2008991689. The next prime is 2008991723. The reversal of 2008991721 is 1271998002.

It is not a de Polignac number, because 2008991721 - 2⁵ = 2008991689 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 2008991721.

It is not an unprimeable number, because it can be changed into a prime (2008991723) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25066 + ... + 68163.

It is an arithmetic number, because the mean of its divisors is an integer number (182917260).

Almost surely, 2^2008991721 is an apocalyptic number.

It is an amenable number.

2008991721 is a deficient number, since it is larger than the sum of its proper divisors (917684439).

2008991721 is a wasteful number, since it uses less digits than its factorization.

2008991721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93896.

The product of its (nonzero) digits is 18144, while the sum is 39.

The square root of 2008991721 is about 44821.7773074652. Note that the first 3 decimals coincide. The cubic root of 2008991721 is about 1261.8063704257.

The spelling of 2008991721 in words is "two billion, eight million, nine hundred ninety-one thousand, seven hundred twenty-one".