2861991 has 12 divisors (see below), whose sum is σ = 4509960. Its totient is φ = 1734480.

The previous prime is 2861977. The next prime is 2862011. The reversal of 2861991 is 1991682.

It is not a de Polignac number, because 2861991 - 2⁶ = 2861927 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2861921) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 14356 + ... + 14553.

It is an arithmetic number, because the mean of its divisors is an integer number (375830).

2^2861991 is an apocalyptic number.

2861991 is a deficient number, since it is larger than the sum of its proper divisors (1647969).

2861991 is a wasteful number, since it uses less digits than its factorization.

2861991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28926 (or 28923 counting only the distinct ones).

The product of its digits is 7776, while the sum is 36.

The square root of 2861991 is about 1691.7420016066. The cubic root of 2861991 is about 141.9785559101.

The spelling of 2861991 in words is "two million, eight hundred sixty-one thousand, nine hundred ninety-one".