2011666621 has 4 divisors (see below), whose sum is σ = 2039223772. Its totient is φ = 1984109472.

The previous prime is 2011666609. The next prime is 2011666651. The reversal of 2011666621 is 1266661102.

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 368256100 + 1643410521 = 19190^2 + 40539^2 .

It is a cyclic number.

It is not a de Polignac number, because 2011666621 - 2⁵ = 2011666589 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 (2011666651) 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, 13778466 + ... + 13778611.

It is an arithmetic number, because the mean of its divisors is an integer number (509805943).

Almost surely, 2^2011666621 is an apocalyptic number.

It is an amenable number.

2011666621 is a deficient number, since it is larger than the sum of its proper divisors (27557151).

2011666621 is an equidigital number, since it uses as much as digits as its factorization.

2011666621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27557150.

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 2011666621 is about 44851.6066713334. The cubic root of 2011666621 is about 1262.3661386159.

The spelling of 2011666621 in words is "two billion, eleven million, six hundred sixty-six thousand, six hundred twenty-one".