18381818387 has 4 divisors (see below), whose sum is σ = 18383406936. Its totient is φ = 18380229840.

The previous prime is 18381818381. The next prime is 18381818401. The reversal of 18381818387 is 78381818381.

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 18381818387 - 2³² = 14086851091 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18381818381) 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, 776789 + ... + 800102.

It is an arithmetic number, because the mean of its divisors is an integer number (4595851734).

Almost surely, 2^18381818387 is an apocalyptic number.

18381818387 is a deficient number, since it is larger than the sum of its proper divisors (1588549).

18381818387 is a wasteful number, since it uses less digits than its factorization.

18381818387 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1588548.

The product of its digits is 2064384, while the sum is 56.

The spelling of 18381818387 in words is "eighteen billion, three hundred eighty-one million, eight hundred eighteen thousand, three hundred eighty-seven".