2161668609 has 48 divisors (see below), whose sum is σ = 3440923200. Its totient is φ = 1302110208.

The previous prime is 2161668601. The next prime is 2161668623. The reversal of 2161668609 is 9068661612.

2161668609 is a `hidden beast` number, since 21 + 6 + 16 + 6 + 8 + 609 = 666.

It is not a de Polignac number, because 2161668609 - 2³ = 2161668601 is a prime.

It is a super-2 number, since 2×2161668609² = 9345622350271989762, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (2161668601) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 385377 + ... + 390945.

It is an arithmetic number, because the mean of its divisors is an integer number (71685900).

Almost surely, 2^2161668609 is an apocalyptic number.

It is an amenable number.

2161668609 is a deficient number, since it is larger than the sum of its proper divisors (1279254591).

2161668609 is a wasteful number, since it uses less digits than its factorization.

2161668609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5694 (or 5691 counting only the distinct ones).

The product of its (nonzero) digits is 186624, while the sum is 45.

The square root of 2161668609 is about 46493.7480635838. The cubic root of 2161668609 is about 1292.9935902985.

The spelling of 2161668609 in words is "two billion, one hundred sixty-one million, six hundred sixty-eight thousand, six hundred nine".