2165581899 has 40 divisors (see below), whose sum is σ = 3489382512. Its totient is φ = 1330551360.

The previous prime is 2165581889. The next prime is 2165581927. The reversal of 2165581899 is 9981855612.

2165581899 is a `hidden beast` number, since 2 + 1 + 6 + 558 + 1 + 89 + 9 = 666.

It is not a de Polignac number, because 2165581899 - 2⁹ = 2165581387 is a prime.

It is a super-2 number, since 2×2165581899² = 9379489922552892402, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (2165581889) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 897004 + ... + 899414.

Almost surely, 2^2165581899 is an apocalyptic number.

2165581899 is a deficient number, since it is larger than the sum of its proper divisors (1323800613).

2165581899 is a wasteful number, since it uses less digits than its factorization.

2165581899 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3289 (or 3280 counting only the distinct ones).

The product of its digits is 1555200, while the sum is 54.

The square root of 2165581899 is about 46535.8130798206. The cubic root of 2165581899 is about 1293.7733596286.

The spelling of 2165581899 in words is "two billion, one hundred sixty-five million, five hundred eighty-one thousand, eight hundred ninety-nine".