18791338123 has 4 divisors (see below), whose sum is σ = 19608352848. Its totient is φ = 17974323400.

The previous prime is 18791338063. The next prime is 18791338141. The reversal of 18791338123 is 32183319781.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 32183319781 = 52391 ⋅614291.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18791338123 is a prime.

It is a super-2 number, since 2×18791338123² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18791338183) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 408507328 + ... + 408507373.

It is an arithmetic number, because the mean of its divisors is an integer number (4902088212).

Almost surely, 2^18791338123 is an apocalyptic number.

18791338123 is a deficient number, since it is larger than the sum of its proper divisors (817014725).

18791338123 is an equidigital number, since it uses as much as digits as its factorization.

18791338123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 817014724.

The product of its digits is 217728, while the sum is 46.

The spelling of 18791338123 in words is "eighteen billion, seven hundred ninety-one million, three hundred thirty-eight thousand, one hundred twenty-three".