18939928417 has 4 divisors (see below), whose sum is σ = 18955315456. Its totient is φ = 18924541380.

The previous prime is 18939928373. The next prime is 18939928457. The reversal of 18939928417 is 71482993981.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 18939928417 - 2²⁷ = 18805710689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18939928457) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7691673 + ... + 7694134.

It is an arithmetic number, because the mean of its divisors is an integer number (4738828864).

Almost surely, 2^18939928417 is an apocalyptic number.

It is an amenable number.

18939928417 is a deficient number, since it is larger than the sum of its proper divisors (15387039).

18939928417 is a wasteful number, since it uses less digits than its factorization.

18939928417 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15387038.

The product of its digits is 7838208, while the sum is 61.

The spelling of 18939928417 in words is "eighteen billion, nine hundred thirty-nine million, nine hundred twenty-eight thousand, four hundred seventeen".