20508321728 has 28 divisors (see below), whose sum is σ = 40707179952. Its totient is φ = 10251394560.

The previous prime is 20508321727. The next prime is 20508321731. The reversal of 20508321728 is 82712380502.

It is a junction number, because it is equal to n+sod(n) for n = 20508321691 and 20508321700.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20508321727) 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, 207101 + ... + 289667.

Almost surely, 2^20508321728 is an apocalyptic number.

It is an amenable number.

20508321728 is a deficient number, since it is larger than the sum of its proper divisors (20198858224).

20508321728 is an equidigital number, since it uses as much as digits as its factorization.

20508321728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86460 (or 86450 counting only the distinct ones).

The product of its (nonzero) digits is 53760, while the sum is 38.

The spelling of 20508321728 in words is "twenty billion, five hundred eight million, three hundred twenty-one thousand, seven hundred twenty-eight".