2161555772 has 12 divisors (see below), whose sum is σ = 3783057600. Its totient is φ = 1080682176.

The previous prime is 2161555771. The next prime is 2161555787. The reversal of 2161555772 is 2775551612.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2161555771) 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, 58229 + ... + 87827.

It is an arithmetic number, because the mean of its divisors is an integer number (315254800).

Almost surely, 2^2161555772 is an apocalyptic number.

It is an amenable number.

2161555772 is a deficient number, since it is larger than the sum of its proper divisors (1621501828).

2161555772 is a wasteful number, since it uses less digits than its factorization.

2161555772 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47860 (or 47858 counting only the distinct ones).

The product of its digits is 147000, while the sum is 41.

The square root of 2161555772 is about 46492.5345835221. The cubic root of 2161555772 is about 1292.9710922375.

The spelling of 2161555772 in words is "two billion, one hundred sixty-one million, five hundred fifty-five thousand, seven hundred seventy-two".