28532021 has 4 divisors (see below), whose sum is σ = 32608032. Its totient is φ = 24456012.

The previous prime is 28532003. The next prime is 28532033. The reversal of 28532021 is 12023582.

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 de Polignac number, because none of the positive numbers 2^k-28532021 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28532041) 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, 2037995 + ... + 2038008.

It is an arithmetic number, because the mean of its divisors is an integer number (8152008).

Almost surely, 2^28532021 is an apocalyptic number.

It is an amenable number.

28532021 is a deficient number, since it is larger than the sum of its proper divisors (4076011).

28532021 is an equidigital number, since it uses as much as digits as its factorization.

28532021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4076010.

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 28532021 is about 5341.5373255272. The cubic root of 28532021 is about 305.5700920369.

The spelling of 28532021 in words is "twenty-eight million, five hundred thirty-two thousand, twenty-one".