2728821 has 8 divisors (see below), whose sum is σ = 3672864. Its totient is φ = 1802000.

The previous prime is 2728819. The next prime is 2728841. The reversal of 2728821 is 1288272.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 2728821 - 2¹ = 2728819 is a prime.

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2728801) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3930 + ... + 4571.

It is an arithmetic number, because the mean of its divisors is an integer number (459108).

2^2728821 is an apocalyptic number.

It is an amenable number.

2728821 is a deficient number, since it is larger than the sum of its proper divisors (944043).

2728821 is a wasteful number, since it uses less digits than its factorization.

2728821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8611.

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

The square root of 2728821 is about 1651.9143440263. The cubic root of 2728821 is about 139.7413762769.

The spelling of 2728821 in words is "two million, seven hundred twenty-eight thousand, eight hundred twenty-one".