2185891 has 4 divisors (see below), whose sum is σ = 2223000. Its totient is φ = 2148784.

The previous prime is 2185889. The next prime is 2185901. The reversal of 2185891 is 1985812.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 2185891 - 2¹ = 2185889 is a prime.

It is a super-4 number, since 4×2185891⁴ (a number of 26 digits) contains 4444 as substring. Note that it is a super-d number also for d = 3.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2185801) 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, 18466 + ... + 18583.

It is an arithmetic number, because the mean of its divisors is an integer number (555750).

2^2185891 is an apocalyptic number.

2185891 is a deficient number, since it is larger than the sum of its proper divisors (37109).

2185891 is an equidigital number, since it uses as much as digits as its factorization.

2185891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37108.

The product of its digits is 5760, while the sum is 34.

The square root of 2185891 is about 1478.4759044367. The cubic root of 2185891 is about 129.7805172234.

The spelling of 2185891 in words is "two million, one hundred eighty-five thousand, eight hundred ninety-one".