2815991 has 4 divisors (see below), whose sum is σ = 2824032. Its totient is φ = 2807952.

The previous prime is 2815979. The next prime is 2815993. The reversal of 2815991 is 1995182.

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 2815991 - 2⁶ = 2815927 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 (2815993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3470 + ... + 4203.

It is an arithmetic number, because the mean of its divisors is an integer number (706008).

2^2815991 is an apocalyptic number.

2815991 is a deficient number, since it is larger than the sum of its proper divisors (8041).

2815991 is an equidigital number, since it uses as much as digits as its factorization.

2815991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8040.

The product of its digits is 6480, while the sum is 35.

The square root of 2815991 is about 1678.0914754566. The cubic root of 2815991 is about 141.2137829719.

The spelling of 2815991 in words is "two million, eight hundred fifteen thousand, nine hundred ninety-one".