21647109728906 has 64 divisors (see below), whose sum is σ = 34590501563904. Its totient is φ = 10124930534400.

The previous prime is 21647109728899. The next prime is 21647109728917. The reversal of 21647109728906 is 60982790174612.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 9746558876 + ... + 9746561096.

It is an arithmetic number, because the mean of its divisors is an integer number (540476586936).

Almost surely, 2^{21647109728906} is an apocalyptic number.

21647109728906 is a deficient number, since it is larger than the sum of its proper divisors (12943391834998).

21647109728906 is a wasteful number, since it uses less digits than its factorization.

21647109728906 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4575.

The product of its (nonzero) digits is 18289152, while the sum is 62.

The spelling of 21647109728906 in words is "twenty-one trillion, six hundred forty-seven billion, one hundred nine million, seven hundred twenty-eight thousand, nine hundred six".