18721660634 has 16 divisors (see below), whose sum is σ = 28642588800. Its totient is φ = 9175836384.

The previous prime is 18721660619. The next prime is 18721660663. The reversal of 18721660634 is 43606612781.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 404267 + ... + 448190.

It is an arithmetic number, because the mean of its divisors is an integer number (1790161800).

Almost surely, 2^18721660634 is an apocalyptic number.

18721660634 is a deficient number, since it is larger than the sum of its proper divisors (9920928166).

18721660634 is a wasteful number, since it uses less digits than its factorization.

18721660634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 852677.

The product of its (nonzero) digits is 290304, while the sum is 44.

The spelling of 18721660634 in words is "eighteen billion, seven hundred twenty-one million, six hundred sixty thousand, six hundred thirty-four".