20013721565443 has 4 divisors (see below), whose sum is σ = 20059942631848. Its totient is φ = 19967500499040.

The previous prime is 20013721565417. The next prime is 20013721565491. The reversal of 20013721565443 is 34456512731002.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20013721565443 - 2³³ = 20005131630851 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20013721565443.

It is not an unprimeable number, because it can be changed into a prime (20013721565843) 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, 23110532553 + ... + 23110533418.

It is an arithmetic number, because the mean of its divisors is an integer number (5014985657962).

Almost surely, 2^{20013721565443} is an apocalyptic number.

20013721565443 is a deficient number, since it is larger than the sum of its proper divisors (46221066405).

20013721565443 is an equidigital number, since it uses as much as digits as its factorization.

20013721565443 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46221066404.

The product of its (nonzero) digits is 604800, while the sum is 43.

The spelling of 20013721565443 in words is "twenty trillion, thirteen billion, seven hundred twenty-one million, five hundred sixty-five thousand, four hundred forty-three".