28605821 has 4 divisors (see below), whose sum is σ = 28968000. Its totient is φ = 28243644.

The previous prime is 28605817. The next prime is 28605827. The reversal of 28605821 is 12850682.

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 28605821 - 2² = 28605817 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28605827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 180971 + ... + 181128.

It is an arithmetic number, because the mean of its divisors is an integer number (7242000).

Almost surely, 2^28605821 is an apocalyptic number.

It is an amenable number.

28605821 is a deficient number, since it is larger than the sum of its proper divisors (362179).

28605821 is an equidigital number, since it uses as much as digits as its factorization.

28605821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 362178.

The product of its (nonzero) digits is 7680, while the sum is 32.

The square root of 28605821 is about 5348.4409878020. The cubic root of 28605821 is about 305.8333244404.

The spelling of 28605821 in words is "twenty-eight million, six hundred five thousand, eight hundred twenty-one".