20385388721 has 8 divisors (see below), whose sum is σ = 21888537984. Its totient is φ = 18916018240.

The previous prime is 20385388703. The next prime is 20385388729. The reversal of 20385388721 is 12788358302.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20385388721 - 2³⁰ = 19311646897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20385388729) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8443445 + ... + 8445858.

It is an arithmetic number, because the mean of its divisors is an integer number (2736067248).

Almost surely, 2^20385388721 is an apocalyptic number.

It is an amenable number.

20385388721 is a deficient number, since it is larger than the sum of its proper divisors (1503149263).

20385388721 is a wasteful number, since it uses less digits than its factorization.

20385388721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16889391.

The product of its (nonzero) digits is 645120, while the sum is 47.

The spelling of 20385388721 in words is "twenty billion, three hundred eighty-five million, three hundred eighty-eight thousand, seven hundred twenty-one".