18631906638 has 8 divisors (see below), whose sum is σ = 37263813288. Its totient is φ = 6210635544.

The previous prime is 18631906609. The next prime is 18631906639. The reversal of 18631906638 is 83660913681.

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

18631906638 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18631906639) 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, 1552658881 + ... + 1552658892.

It is an arithmetic number, because the mean of its divisors is an integer number (4657976661).

Almost surely, 2^18631906638 is an apocalyptic number.

18631906638 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18631906638 is a wasteful number, since it uses less digits than its factorization.

18631906638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3105317778.

The product of its (nonzero) digits is 1119744, while the sum is 51.

The spelling of 18631906638 in words is "eighteen billion, six hundred thirty-one million, nine hundred six thousand, six hundred thirty-eight".