28327821 has 4 divisors (see below), whose sum is σ = 37770432. Its totient is φ = 18885212.

The previous prime is 28327813. The next prime is 28327823. The reversal of 28327821 is 12872382.

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.

It is a cyclic number.

It is not a de Polignac number, because 28327821 - 2³ = 28327813 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28327823) 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, 4721301 + ... + 4721306.

It is an arithmetic number, because the mean of its divisors is an integer number (9442608).

Almost surely, 2^28327821 is an apocalyptic number.

It is an amenable number.

28327821 is a deficient number, since it is larger than the sum of its proper divisors (9442611).

28327821 is an equidigital number, since it uses as much as digits as its factorization.

28327821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9442610.

The product of its digits is 10752, while the sum is 33.

The square root of 28327821 is about 5322.3886554817. The cubic root of 28327821 is about 304.8393707625.

The spelling of 28327821 in words is "twenty-eight million, three hundred twenty-seven thousand, eight hundred twenty-one".