2728991 has 4 divisors (see below), whose sum is σ = 2734032. Its totient is φ = 2723952.

The previous prime is 2728981. The next prime is 2728997. The reversal of 2728991 is 1998272.

2728991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2728991 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 (2728997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1595 + ... + 2828.

It is an arithmetic number, because the mean of its divisors is an integer number (683508).

2^2728991 is an apocalyptic number.

2728991 is a deficient number, since it is larger than the sum of its proper divisors (5041).

2728991 is an equidigital number, since it uses as much as digits as its factorization.

2728991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5040.

The product of its digits is 18144, while the sum is 38.

The square root of 2728991 is about 1651.9657986774. The cubic root of 2728991 is about 139.7442780845.

The spelling of 2728991 in words is "two million, seven hundred twenty-eight thousand, nine hundred ninety-one".