2828721 has 16 divisors (see below), whose sum is σ = 4400000. Its totient is φ = 1615824.

The previous prime is 2828717. The next prime is 2828731. The reversal of 2828721 is 1278282.

It is a happy number.

2828721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 2828721 - 2² = 2828717 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2828731) 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 15 ways as a sum of consecutive naturals, for example, 346 + ... + 2403.

It is an arithmetic number, because the mean of its divisors is an integer number (275000).

2^2828721 is an apocalyptic number.

2828721 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

2828721 is a deficient number, since it is larger than the sum of its proper divisors (1571279).

2828721 is an equidigital number, since it uses as much as digits as its factorization.

2828721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2773 (or 2759 counting only the distinct ones).

The product of its digits is 3584, while the sum is 30.

The square root of 2828721 is about 1681.8801978738. The cubic root of 2828721 is about 141.4262539886.

The spelling of 2828721 in words is "two million, eight hundred twenty-eight thousand, seven hundred twenty-one".