2805991 has 4 divisors (see below), whose sum is σ = 2845584. Its totient is φ = 2766400.

The previous prime is 2805989. The next prime is 2806007. The reversal of 2805991 is 1995082.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1995082 = 2 ⋅997541.

It is a cyclic number.

It is not a de Polignac number, because 2805991 - 2¹ = 2805989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2805911) 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, 19690 + ... + 19831.

It is an arithmetic number, because the mean of its divisors is an integer number (711396).

2^2805991 is an apocalyptic number.

2805991 is a deficient number, since it is larger than the sum of its proper divisors (39593).

2805991 is an equidigital number, since it uses as much as digits as its factorization.

2805991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39592.

The product of its (nonzero) digits is 6480, while the sum is 34.

The square root of 2805991 is about 1675.1092501685. The cubic root of 2805991 is about 141.0464277134.

The spelling of 2805991 in words is "two million, eight hundred five thousand, nine hundred ninety-one".