28557321 has 8 divisors (see below), whose sum is σ = 41005440. Its totient is φ = 17573712.

The previous prime is 28557313. The next prime is 28557349. The reversal of 28557321 is 12375582.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 28557321 - 2³ = 28557313 is a prime.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (28557311) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 366081 + ... + 366158.

It is an arithmetic number, because the mean of its divisors is an integer number (5125680).

Almost surely, 2^28557321 is an apocalyptic number.

It is an amenable number.

28557321 is a deficient number, since it is larger than the sum of its proper divisors (12448119).

28557321 is a wasteful number, since it uses less digits than its factorization.

28557321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 732255.

The product of its digits is 16800, while the sum is 33.

The square root of 28557321 is about 5343.9050328388. The cubic root of 28557321 is about 305.6603840331.

The spelling of 28557321 in words is "twenty-eight million, five hundred fifty-seven thousand, three hundred twenty-one".