18723686779 has 4 divisors (see below), whose sum is σ = 21398499184. Its totient is φ = 16048874376.

The previous prime is 18723686717. The next prime is 18723686827. The reversal of 18723686779 is 97768632781.

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 18723686779 - 2¹¹ = 18723684731 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 18723686779.

It is not an unprimeable number, because it can be changed into a prime (18723686879) 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, 1337406192 + ... + 1337406205.

It is an arithmetic number, because the mean of its divisors is an integer number (5349624796).

Almost surely, 2^18723686779 is an apocalyptic number.

18723686779 is a deficient number, since it is larger than the sum of its proper divisors (2674812405).

18723686779 is an equidigital number, since it uses as much as digits as its factorization.

18723686779 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2674812404.

The product of its digits is 42674688, while the sum is 64.

The spelling of 18723686779 in words is "eighteen billion, seven hundred twenty-three million, six hundred eighty-six thousand, seven hundred seventy-nine".