28721508723 has 12 divisors (see below), whose sum is σ = 42498493128. Its totient is φ = 18680655840.

The previous prime is 28721508719. The next prime is 28721508763. The reversal of 28721508723 is 32780512782.

28721508723 is a `hidden beast` number, since 2 + 8 + 72 + 1 + 508 + 72 + 3 = 666.

It is not a de Polignac number, because 28721508723 - 2² = 28721508719 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28721508763) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 38917665 + ... + 38918402.

It is an arithmetic number, because the mean of its divisors is an integer number (3541541094).

Almost surely, 2^28721508723 is an apocalyptic number.

28721508723 is a deficient number, since it is larger than the sum of its proper divisors (13776984405).

28721508723 is a wasteful number, since it uses less digits than its factorization.

28721508723 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77836114 (or 77836111 counting only the distinct ones).

The product of its (nonzero) digits is 376320, while the sum is 45.

The spelling of 28721508723 in words is "twenty-eight billion, seven hundred twenty-one million, five hundred eight thousand, seven hundred twenty-three".