18994187517 has 4 divisors (see below), whose sum is σ = 25325583360. Its totient is φ = 12662791676.

The previous prime is 18994187489. The next prime is 18994187521. The reversal of 18994187517 is 71578149981.

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 18994187517 - 2⁷ = 18994187389 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18994187417) 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, 3165697917 + ... + 3165697922.

It is an arithmetic number, because the mean of its divisors is an integer number (6331395840).

Almost surely, 2^18994187517 is an apocalyptic number.

It is an amenable number.

18994187517 is a deficient number, since it is larger than the sum of its proper divisors (6331395843).

18994187517 is an equidigital number, since it uses as much as digits as its factorization.

18994187517 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6331395842.

The product of its digits is 5080320, while the sum is 60.

The spelling of 18994187517 in words is "eighteen billion, nine hundred ninety-four million, one hundred eighty-seven thousand, five hundred seventeen".