28480221 has 96 divisors (see below), whose sum is σ = 56908800. Its totient is φ = 13880160.

The previous prime is 28480213. The next prime is 28480237. The reversal of 28480221 is 12208482.

It is not a de Polignac number, because 28480221 - 2³ = 28480213 is a prime.

It is a super-2 number, since 2×28480221² = 1622245976417682, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28480241) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 276456 + ... + 276558.

It is an arithmetic number, because the mean of its divisors is an integer number (592800).

Almost surely, 2^28480221 is an apocalyptic number.

28480221 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

28480221 is a deficient number, since it is larger than the sum of its proper divisors (28428579).

28480221 is a wasteful number, since it uses less digits than its factorization.

28480221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156 (or 143 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 27.

The square root of 28480221 is about 5336.6863314233. The cubic root of 28480221 is about 305.3850587678.

It can be divided in two parts, 28 and 480221, that added together give a square (480249 = 693²).

The spelling of 28480221 in words is "twenty-eight million, four hundred eighty thousand, two hundred twenty-one".