2161206645 has 48 divisors (see below), whose sum is σ = 3761484480. Its totient is φ = 1059122688.

The previous prime is 2161206629. The next prime is 2161206653. The reversal of 2161206645 is 5466021612.

It is not a de Polignac number, because 2161206645 - 2⁴ = 2161206629 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 588826 + ... + 592484.

It is an arithmetic number, because the mean of its divisors is an integer number (78364260).

Almost surely, 2^2161206645 is an apocalyptic number.

It is an amenable number.

2161206645 is a deficient number, since it is larger than the sum of its proper divisors (1600277835).

2161206645 is a wasteful number, since it uses less digits than its factorization.

2161206645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3926 (or 3913 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 33.

The square root of 2161206645 is about 46488.7797753393. The cubic root of 2161206645 is about 1292.9014764188.

The spelling of 2161206645 in words is "two billion, one hundred sixty-one million, two hundred six thousand, six hundred forty-five".