2185659891 has 6 divisors (see below), whose sum is σ = 3157064300. Its totient is φ = 1457106588.

The previous prime is 2185659877. The next prime is 2185659911. The reversal of 2185659891 is 1989565812.

It is not a de Polignac number, because 2185659891 - 2⁹ = 2185659379 is a prime.

It is a super-2 number, since 2×2185659891² = 9554218318252263762, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2185659821) 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, 121425541 + ... + 121425558.

Almost surely, 2^2185659891 is an apocalyptic number.

2185659891 is a deficient number, since it is larger than the sum of its proper divisors (971404409).

2185659891 is a wasteful number, since it uses less digits than its factorization.

2185659891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 242851105 (or 242851102 counting only the distinct ones).

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

The square root of 2185659891 is about 46751.0416033697. The cubic root of 2185659891 is about 1297.7594326814.

The spelling of 2185659891 in words is "two billion, one hundred eighty-five million, six hundred fifty-nine thousand, eight hundred ninety-one".