18403888643 has 8 divisors (see below), whose sum is σ = 21198630912. Its totient is φ = 15650550216.

The previous prime is 18403888639. The next prime is 18403888663. The reversal of 18403888643 is 34688830481.

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

It is not a de Polignac number, because 18403888643 - 2² = 18403888639 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18403888663) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10350005 + ... + 10351782.

It is an arithmetic number, because the mean of its divisors is an integer number (2649828864).

Almost surely, 2^18403888643 is an apocalyptic number.

18403888643 is a deficient number, since it is larger than the sum of its proper divisors (2794742269).

18403888643 is a wasteful number, since it uses less digits than its factorization.

18403888643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20701921.

The product of its (nonzero) digits is 3538944, while the sum is 53.

The spelling of 18403888643 in words is "eighteen billion, four hundred three million, eight hundred eighty-eight thousand, six hundred forty-three".