18923993489578 has 4 divisors (see below), whose sum is σ = 28385990234370. Its totient is φ = 9461996744788.

The previous prime is 18923993489509. The next prime is 18923993489587. The reversal of 18923993489578 is 87598439932981.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 11040381807849 + 7883611681729 = 3322707^2 + 2807777^2 .

It is a Smith number, since the sum of its digits (85) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 18923993489495 and 18923993489504.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4730998372393 + ... + 4730998372396.

Almost surely, 2^{18923993489578} is an apocalyptic number.

18923993489578 is a deficient number, since it is larger than the sum of its proper divisors (9461996744792).

18923993489578 is an equidigital number, since it uses as much as digits as its factorization.

18923993489578 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9461996744791.

The product of its digits is 8465264640, while the sum is 85.

The spelling of 18923993489578 in words is "eighteen trillion, nine hundred twenty-three billion, nine hundred ninety-three million, four hundred eighty-nine thousand, five hundred seventy-eight".