2861891 has 4 divisors (see below), whose sum is σ = 2872800. Its totient is φ = 2850984.

The previous prime is 2861869. The next prime is 2861897. The reversal of 2861891 is 1981682.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1981682 = 2 ⋅990841.

It is a cyclic number.

It is not a de Polignac number, because 2861891 - 2¹⁸ = 2599747 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2861897) 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, 5051 + ... + 5588.

It is an arithmetic number, because the mean of its divisors is an integer number (718200).

2^2861891 is an apocalyptic number.

2861891 is a deficient number, since it is larger than the sum of its proper divisors (10909).

2861891 is a wasteful number, since it uses less digits than its factorization.

2861891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10908.

The product of its digits is 6912, while the sum is 35.

The square root of 2861891 is about 1691.7124460144. The cubic root of 2861891 is about 141.9769022803.

The spelling of 2861891 in words is "two million, eight hundred sixty-one thousand, eight hundred ninety-one".