28648221 has 8 divisors (see below), whose sum is σ = 43654464. Its totient is φ = 16370400.

The previous prime is 28648199. The next prime is 28648237. The reversal of 28648221 is 12284682.

It is a happy number.

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

It is not a de Polignac number, because 28648221 - 2⁶ = 28648157 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28646221) 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 7 ways as a sum of consecutive naturals, for example, 682080 + ... + 682121.

It is an arithmetic number, because the mean of its divisors is an integer number (5456808).

Almost surely, 2^28648221 is an apocalyptic number.

28648221 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

28648221 is a deficient number, since it is larger than the sum of its proper divisors (15006243).

28648221 is a wasteful number, since it uses less digits than its factorization.

28648221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1364211.

The product of its digits is 12288, while the sum is 33.

The square root of 28648221 is about 5352.4032919802. The cubic root of 28648221 is about 305.9843535081.

The spelling of 28648221 in words is "twenty-eight million, six hundred forty-eight thousand, two hundred twenty-one".