2628721 has 4 divisors (see below), whose sum is σ = 2632000. Its totient is φ = 2625444.

The previous prime is 2628713. The next prime is 2628737. The reversal of 2628721 is 1278262.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 2628721 - 2³ = 2628713 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2628721.

It is not an unprimeable number, because it can be changed into a prime (2628781) 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, 460 + ... + 2338.

It is an arithmetic number, because the mean of its divisors is an integer number (658000).

2^2628721 is an apocalyptic number.

It is an amenable number.

2628721 is a deficient number, since it is larger than the sum of its proper divisors (3279).

2628721 is a wasteful number, since it uses less digits than its factorization.

2628721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3278.

The product of its digits is 2688, while the sum is 28.

The square root of 2628721 is about 1621.3330934759. Note that the first 3 decimals coincide. The cubic root of 2628721 is about 138.0113587234.

The spelling of 2628721 in words is "two million, six hundred twenty-eight thousand, seven hundred twenty-one".