28052821 has 4 divisors (see below), whose sum is σ = 28408000. Its totient is φ = 27697644.

The previous prime is 28052819. The next prime is 28052837. The reversal of 28052821 is 12825082.

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 an emirpimes, since its reverse is a distinct semiprime: 12825082 = 2 ⋅6412541.

It is a cyclic number.

It is not a de Polignac number, because 28052821 - 2¹ = 28052819 is a prime.

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 28052821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28053821) 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, 177471 + ... + 177628.

It is an arithmetic number, because the mean of its divisors is an integer number (7102000).

Almost surely, 2^28052821 is an apocalyptic number.

It is an amenable number.

28052821 is a deficient number, since it is larger than the sum of its proper divisors (355179).

28052821 is an equidigital number, since it uses as much as digits as its factorization.

28052821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 355178.

The product of its (nonzero) digits is 2560, while the sum is 28.

The square root of 28052821 is about 5296.4913858138. The cubic root of 28052821 is about 303.8497244631.

The spelling of 28052821 in words is "twenty-eight million, fifty-two thousand, eight hundred twenty-one".