21647109728968 has 16 divisors (see below), whose sum is σ = 41451912247680. Its totient is φ = 10593266462928.

The previous prime is 21647109728963. The next prime is 21647109728983. The reversal of 21647109728968 is 86982790174612.

It is a junction number, because it is equal to n+sod(n) for n = 21647109728897 and 21647109728906.

It is not an unprimeable number, because it can be changed into a prime (21647109728963) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 28786049796 + ... + 28786050547.

It is an arithmetic number, because the mean of its divisors is an integer number (2590744515480).

Almost surely, 2^{21647109728968} is an apocalyptic number.

It is an amenable number.

21647109728968 is a deficient number, since it is larger than the sum of its proper divisors (19804802518712).

21647109728968 is a wasteful number, since it uses less digits than its factorization.

21647109728968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57572100396 (or 57572100392 counting only the distinct ones).

The product of its (nonzero) digits is 146313216, while the sum is 70.

The spelling of 21647109728968 in words is "twenty-one trillion, six hundred forty-seven billion, one hundred nine million, seven hundred twenty-eight thousand, nine hundred sixty-eight".