28366321 has 4 divisors (see below), whose sum is σ = 29344500. Its totient is φ = 27388144.

The previous prime is 28366313. The next prime is 28366343. The reversal of 28366321 is 12366382.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 19927296 + 8439025 = 4464^2 + 2905^2 .

It is a cyclic number.

It is not a de Polignac number, because 28366321 - 2³ = 28366313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28366361) 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, 489046 + ... + 489103.

It is an arithmetic number, because the mean of its divisors is an integer number (7336125).

Almost surely, 2^28366321 is an apocalyptic number.

It is an amenable number.

28366321 is a deficient number, since it is larger than the sum of its proper divisors (978179).

28366321 is an equidigital number, since it uses as much as digits as its factorization.

28366321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 978178.

The product of its digits is 10368, while the sum is 31.

The square root of 28366321 is about 5326.0042245571. The cubic root of 28366321 is about 304.9774094170.

The spelling of 28366321 in words is "twenty-eight million, three hundred sixty-six thousand, three hundred twenty-one".