28543221 has 48 divisors (see below), whose sum is σ = 51667200. Its totient is φ = 14805504.

The previous prime is 28543211. The next prime is 28543223. The reversal of 28543221 is 12234582.

It is not a de Polignac number, because 28543221 - 2⁵ = 28543189 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28543223) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 30600 + ... + 31518.

It is an arithmetic number, because the mean of its divisors is an integer number (1076400).

Almost surely, 2^28543221 is an apocalyptic number.

28543221 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

28543221 is a deficient number, since it is larger than the sum of its proper divisors (23123979).

28543221 is a wasteful number, since it uses less digits than its factorization.

28543221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 978 (or 975 counting only the distinct ones).

The product of its digits is 3840, while the sum is 27.

The square root of 28543221 is about 5342.5856099832. The cubic root of 28543221 is about 305.6100697789.

The spelling of 28543221 in words is "twenty-eight million, five hundred forty-three thousand, two hundred twenty-one".