18387513673 has 4 divisors (see below), whose sum is σ = 18884473540. Its totient is φ = 17890553808.

The previous prime is 18387513643. The next prime is 18387513689. The reversal of 18387513673 is 37631578381.

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

It can be written as a sum of positive squares in 2 ways, for example, as 14236546489 + 4150967184 = 119317^2 + 64428^2 .

It is a cyclic number.

It is not a de Polignac number, because 18387513673 - 2¹³ = 18387505481 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 18387513673.

It is not an unprimeable number, because it can be changed into a prime (18387513643) 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, 248479878 + ... + 248479951.

It is an arithmetic number, because the mean of its divisors is an integer number (4721118385).

Almost surely, 2^18387513673 is an apocalyptic number.

It is an amenable number.

18387513673 is a deficient number, since it is larger than the sum of its proper divisors (496959867).

18387513673 is an equidigital number, since it uses as much as digits as its factorization.

18387513673 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 496959866.

The product of its digits is 2540160, while the sum is 52.

The spelling of 18387513673 in words is "eighteen billion, three hundred eighty-seven million, five hundred thirteen thousand, six hundred seventy-three".