2011522721 has 4 divisors (see below), whose sum is σ = 2166255252. Its totient is φ = 1856790192.

The previous prime is 2011522693. The next prime is 2011522787. The reversal of 2011522721 is 1272251102.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 136632721 + 1874890000 = 11689^2 + 43300^2 .

It is a cyclic number.

It is not a de Polignac number, because 2011522721 - 2⁶ = 2011522657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2011522921) 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, 77366246 + ... + 77366271.

It is an arithmetic number, because the mean of its divisors is an integer number (541563813).

Almost surely, 2^2011522721 is an apocalyptic number.

It is an amenable number.

2011522721 is a deficient number, since it is larger than the sum of its proper divisors (154732531).

2011522721 is a wasteful number, since it uses less digits than its factorization.

2011522721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 154732530.

The product of its (nonzero) digits is 560, while the sum is 23.

The square root of 2011522721 is about 44850.0024637680. The cubic root of 2011522721 is about 1262.3360377339.

Adding to 2011522721 its reverse (1272251102), we get a palindrome (3283773823).

The spelling of 2011522721 in words is "two billion, eleven million, five hundred twenty-two thousand, seven hundred twenty-one".