28501321 has 4 divisors (see below), whose sum is σ = 28512000. Its totient is φ = 28490644.

The previous prime is 28501241. The next prime is 28501327. The reversal of 28501321 is 12310582.

It is the 2180-th star number.

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 a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 28501321 - 2¹⁵ = 28468553 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28501292 and 28501301.

It is not an unprimeable number, because it can be changed into a prime (28501327) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2580 + ... + 7978.

It is an arithmetic number, because the mean of its divisors is an integer number (7128000).

Almost surely, 2^28501321 is an apocalyptic number.

It is an amenable number.

28501321 is a deficient number, since it is larger than the sum of its proper divisors (10679).

28501321 is an equidigital number, since it uses as much as digits as its factorization.

28501321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10678.

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 28501321 is about 5338.6628475677. The cubic root of 28501321 is about 305.4604565220.

The spelling of 28501321 in words is "twenty-eight million, five hundred one thousand, three hundred twenty-one".