2162021661 has 6 divisors (see below), whose sum is σ = 3122920190. Its totient is φ = 1441347768.

The previous prime is 2162021621. The next prime is 2162021669. The reversal of 2162021661 is 1661202612.

2162021661 is a `hidden beast` number, since 21 + 620 + 2 + 16 + 6 + 1 = 666.

2162021661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 1328602500 + 833419161 = 36450^2 + 28869^2 .

It is not a de Polignac number, because 2162021661 - 2⁹ = 2162021149 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 (2162021669) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 120112306 + ... + 120112323.

Almost surely, 2^2162021661 is an apocalyptic number.

It is an amenable number.

2162021661 is a deficient number, since it is larger than the sum of its proper divisors (960898529).

2162021661 is a wasteful number, since it uses less digits than its factorization.

2162021661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 240224635 (or 240224632 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 2162021661 is about 46497.5446771117. The cubic root of 2162021661 is about 1293.0639786891.

The spelling of 2162021661 in words is "two billion, one hundred sixty-two million, twenty-one thousand, six hundred sixty-one".