18385516999 has 4 divisors (see below), whose sum is σ = 18607029336. Its totient is φ = 18164004664.

The previous prime is 18385516997. The next prime is 18385517093. The reversal of 18385516999 is 99961558381.

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

It is a cyclic number.

It is not a de Polignac number, because 18385516999 - 2¹ = 18385516997 is a prime.

It is a super-3 number, since 3×18385516999³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18385516999.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18385516993) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 110756044 + ... + 110756209.

It is an arithmetic number, because the mean of its divisors is an integer number (4651757334).

Almost surely, 2^18385516999 is an apocalyptic number.

18385516999 is a deficient number, since it is larger than the sum of its proper divisors (221512337).

18385516999 is an equidigital number, since it uses as much as digits as its factorization.

18385516999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 221512336.

The product of its digits is 20995200, while the sum is 64.

The spelling of 18385516999 in words is "eighteen billion, three hundred eighty-five million, five hundred sixteen thousand, nine hundred ninety-nine".