18385366999 has 4 divisors (see below), whose sum is σ = 18686766520. Its totient is φ = 18083967480.

The previous prime is 18385366991. The next prime is 18385367029. The reversal of 18385366999 is 99966358381.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 99966358381 = 1621 ⋅61669561.

It is a cyclic number.

It is not a de Polignac number, because 18385366999 - 2³ = 18385366991 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18385366991) 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, 150699669 + ... + 150699790.

It is an arithmetic number, because the mean of its divisors is an integer number (4671691630).

Almost surely, 2^18385366999 is an apocalyptic number.

18385366999 is a deficient number, since it is larger than the sum of its proper divisors (301399521).

18385366999 is an equidigital number, since it uses as much as digits as its factorization.

18385366999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 301399520.

The product of its digits is 75582720, while the sum is 67.

The spelling of 18385366999 in words is "eighteen billion, three hundred eighty-five million, three hundred sixty-six thousand, nine hundred ninety-nine".