28345738221 has 48 divisors (see below), whose sum is σ = 45790243200. Its totient is φ = 16817963904.

The previous prime is 28345738207. The next prime is 28345738231. The reversal of 28345738221 is 12283754382.

28345738221 is a `hidden beast` number, since 28 + 34 + 573 + 8 + 2 + 21 = 666.

It is not a de Polignac number, because 28345738221 - 2⁵ = 28345738189 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28345738231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 106240 + ... + 260726.

It is an arithmetic number, because the mean of its divisors is an integer number (953963400).

Almost surely, 2^28345738221 is an apocalyptic number.

It is an amenable number.

28345738221 is a deficient number, since it is larger than the sum of its proper divisors (17444504979).

28345738221 is a wasteful number, since it uses less digits than its factorization.

28345738221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154578 (or 154575 counting only the distinct ones).

The product of its digits is 645120, while the sum is 45.

The spelling of 28345738221 in words is "twenty-eight billion, three hundred forty-five million, seven hundred thirty-eight thousand, two hundred twenty-one".