18939539642 has 8 divisors (see below), whose sum is σ = 28702189236. Its totient is φ = 9372143232.

The previous prime is 18939539599. The next prime is 18939539651. The reversal of 18939539642 is 24693593981.

It is a Cunningham number, because it is equal to 137621²+1.

It can be written as a sum of positive squares in 2 ways, for example, as 18939539641 + 1 = 137621^2 + 1^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 48813053 + ... + 48813440.

Almost surely, 2^18939539642 is an apocalyptic number.

18939539642 is a deficient number, since it is larger than the sum of its proper divisors (9762649594).

18939539642 is an equidigital number, since it uses as much as digits as its factorization.

18939539642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97626592.

The product of its digits is 12597120, while the sum is 59.

The spelling of 18939539642 in words is "eighteen billion, nine hundred thirty-nine million, five hundred thirty-nine thousand, six hundred forty-two".